Hey there SomeGuy. I really struggle with bacne on TRT and haven't found-out any consistently successful way of treating it. If you have something that works for you, would you mind sharing info about it?
Sure! I've been able to mostly keep it under control but still have a pimple here and there and occasional larger breakouts. The key seems to be showering asap after you sweat (after working out, working in the yard, whatever), and using salicylic acid and benzyl peroxide products. It also helps to keep any chest or back hair trimmed down to keep those areas dryer and cleaner, and let the products get to your skin more easily.
I use a salicylic acid body wash (any body wash with 2% salicylic acid should do the trick), salicylic acid body spray (.5% - 2%, depending on how much it dries your skin), and benzyl peroxide 2.5% gel or paste. I use the body wash all over every time I shower, the salicylic acid spray all over my back and chest once or twice per day, and the benzyl peroxide on existing pimples and any areas that often break out just before bed. You can mix and match however you like but the idea is to apply both products 1-3 times per day, as much as your skin can stand without over drying.
I also use salicylic acid cleaning pads and the benzyl peroxide gel to spot treat the occasional pimples that pop up on my face.
If a month or two of strictly following the above doesn't do the trick the next step would be to cut down on your T dosage, or see a dermatologist for a prescription solution. Be wary and do your research if they prescribe Accutane. It can have permanent side effects.