Alright, you're a fairly young (16-23), yet fairly serious lifter. Your body should be filled up with testosterone and your hormones are raging. So, this means you are likely dealing with one of two things, or both. That is:
1) dealing with keeping you skin good/acne free, and/or
2) constant boners.
Let's start with the first one, your skin. Now, if you're Native American or something, you may be blessed with some awesome no acne genetics; but if you're not, then holy S*** is this getting annoying. At this point, you've probably tried everything. EVERY-F***ING-THING: skin creams, showering stuff, constantly changing your bed sheets/blankets/pillow cases, oil-free this and that, taking a shower two to three times a day, and so on--but none of it works. Why is this? What gives?
Here's the first thing: your diet sucks! That's right, you may think your diet is awesome, but it isn't balanced. You've been neglecting your micro-nutrient intake. Huh, you take a multi? Yea, that isn't enough. Not even close. Sorry.
Here is a highly contributing problem: you're lifting a lot of weights, and thus taking in a lot of protein. This isn't necessarily a bad thing, but it becomes one when you don't balance it out. When your body breaks down protein, a bit of acid is produced. Your body's PH level becomes very acidic. Your body likes to stay in a state of homeostasis, and will try very hard to be in that balanced state. So, your body is going to try getting rid of that extra acid, in whatever way possible. If you were to test your urine (very simple to do: just get some PH testing strips and pee on them), you'd see your body's PH level is very acidic. Urine isn't the only way your body will try to excrete the acid. Did you guess it, yet? That's right, your body will push it to/through your skin, causing some ugly acne. Not only this, but it'll weaken your bones--if your bones are weak, you aren't going to get big!
So, we must balance out this massive amount of protein-induced acidity. What do we do? Eat less protein? Hell no. We need to get a proper amount of bases into our bodies. The first thing that should have clicked into your mind is calcium: that's all that Tums (the acid reflux/heartbearn stuff) is, just straight up calcium plus some flavoring and coloring. So, obviously, calcium is a great choice to neutralize the acidity. You should know by now that the presence of vitamin-D is very beneficial to calcium. You should also know by now that calcium is good for your bones--I'm sure you've seen a commercial for milk.
The next supplement you should be taking in is magnesium. This has the same benefits as calcium: it's a base to balance your PH level, and also helps with your bone mineral density, when you take in calcium. Furthermore, magnesium has been seen to help with depression. So, with the magnesium supplementation plus your skin finally clearing up, you should start being pretty happy and not so gloomy.
Zinc. Ahh, good old zinc. Seriously there are so many benefits of zinc, that I'd have to write another page up for you, just to list them all out. In short, zinc: (1) is a base; (2) helps with bone mineralization; (3) helps build and repair and cells and tissues (this means it improves muscle growth, nails, hair, and your SKIN, among other things); and (4) plays a role in enabling vitamin-A function (more on vitamin-A later).
So, as you can see, upping your mineral intake is very beneficial. You may also consider phosphorous, copper, and other things; but zinc, magnesium, and calcium are the big three when it comes to your bases. Now, we're going to start looking at vitamins.
We've already talked about vitamin-D, as it helps with calcium's effects. Vitamin-E (note: get a vitamin-E supplement that is a mix of tocerpherols) and vitamin-A are known to be beneficial to your skin. Not only this, but having them around the same time works in a synergistic way. Adding vitamin-C to the mix is just even more beneficial. The three of these are antioxidants and help repair your S***y skin with new, healthy cells.
The last supplement I want to quickly bring up is fish oil. Just like zinc, this is one of those supplements that has a multitude of benefits to taking it. What you need to know for this topic is two things: (1) it helps with stress, and (2) it's an anti-inflammatory. These two things will help improve your skin.
So, now that supplements are covered, let's quickly cover a few other things about skin care. First, showering. You're probably doing it way too much. Shower once a day--at most. Yes, I really did just say that. I know, it goes against what you've always been told, but showering too much really ruins your skin. If your face is sweaty or dirty from something, simply splash some water onto your face, instead of washing it. Showering too much will cause you to erode the outer layers of your skin. When this happens, your skin becomes dry. When your skin becomes dry, it starts to produce a lot of oil; this oil will clog your pores and cause acne. So, a light bit of oil-free moisturizer may be beneficial to you to use every now and then. Another thing that will/may dry your skin out is when you're in your car with the heat blasting. Instead of blasting the heat, keep it on low, have the vents blowing away from your face, and wear warmer clothes.
For "acne-fighting" products, all you really need are two things: for the shower, use a wash that is 2% salicylic acid; for a cream/gel to use during the day/before bed, get one that is 10% benzoyl peroxide (if your skin is sensitive to it, apply your moisturizer about 10 minutes or so later). If, after a while, you are looking good, but just need that final finishing touch, you can try a mask with a clay base. I would recommend Aztec Secret's Indian Healing Clay. You can get this stuff at Whole Foods for like $8, and cheaper on Amazon. Lastly, I have no actual concrete support to this one, but I'm still saying it: take care of your oral hygiene and brush your teeth twice a day; I have my reasoning to believe it'll help with your skin (acne is filled with bacteria, so keeping the bacteria that isn't needed out of your body will mean your body isn't going to be forced to excrete it).
The increase of all those vitamins and minerals will improve not only your skin, but many other things. Bone health, muscle growth, sleep, depression, digestion, heart health, brain health, sexual function, mood, an all around sense of well being, immune function and fighting diseases, hormonal regulation, increased confidence, stress management, blood sugar balancing, and more! Your life is going to be a lot better.
Alright, we have finally made it to the second one! Well, sorry, but I can tell you much/offer you any real advice, other then to tell you to cut it off. Well, you could also try for "stim-dick," but I'd rather not be unable to get an erection at all (along with so many other health complications that'll likely happen). You may think, "get a girlfriend to take care of it" is a good answer. No, it isn't. Your body ought to be pretty good looking by now, so you should have a hot girlfriend, who makes you hard upon sight (thus, still having constant erections). If that isn't the case, then you should be focusing on getting a better body to get with that hottie you work with or dump your current girlfriend cause she isn't hot. So, there isn't any real/good advice for this problem, other than cut it off or wait until you get older.