What Causes Random Pimple Like Bumps?

I have random pimple like bumps 1 on face had 3-4 tiny ones on stomach 1 on arm 3 on breast they are small look like pimple sometimes you can pop it. They tiniest ones on stomach I picked at had tiny scab. I also thought I had ingrown hair at very edge of pubic hair been there a few week now slow to heal usually fills with pus an blood a few times about the size of a nickel. My husband has just started withthese pimple he had 1 on leg an one on hip today has 2 in armpit they don't seem to occur at the same time. Appearance is like pimple or ingrown hair. I have been married 13 years no one has strayed just concerned what this is. Before o married I had 1 unprotected encounter could this be HIV would I be sick? This jas been occurring @ 3 months for me an 2 weeks for my husband. I also have crohns - ulcerative colitis and acid reflux I have taken prednisone for @ 2 months completed it in march. My husband has diverticulitis a few episodes in April was hospitalized for it. Please help