Spots on back plzz help asap plese do help卢

hi i keep getting spots on my back and chest. they are internal like im 15 male. I had 2 on my chest squeezed 1 it got redder no pus came out did more and blood did. These are like on my back to. is this with puberty or wht? im very worried i dont want my skin ruined or scarred. I had injection 4 weeks back could it be side effects? I dnt no y all of the sudden im gettin them there. should i leave them any tips? is 2 do with testosterone/? Thanks soo

my 15 yr old son gets them too, it is getting warmer out and you sweat more, causing acne. Also since you are growing more hair it is that also. I have found that if you use a acne scrub on one of those shower brushes ( so you can reach your back) it works great it helps open those bumps so the hairs can get through faster. GOOD LUCK