Possible skin infection, please advise best course of action to treat.

I’ve noticed this weird group of red spots appear on my lower back. Any ideas what it could be?

I roll ju-jitsu and there was talk in the gym recently about skin infections so it may be that.

Here what it looks like: https://imgur.com/a/JYTLdbo

I’m 24, male, 75kg and a non smoker.