What can this be !??

I heard some people say that their baby get a rash around their mouth from teething but I’m not sure this might be it. I’m a mom of 2 kids and my first didn’t experience anything other than a bit discomfort my 2nd baby he is 7 months and he had fever for two days of 102-101 and yesterday I noticed he has spots on both arms but now is on his mouth back of neck back , his butt and private area. He is exclusively BF and I also noticed one dot similar to his on my arm. Has anyone seen something like this before!? Is it related to teething or it could be an allergic reaction to something?