What can cause this?

I’ve been getting what looks like acne on my right shin (only here) and it doesn’t clear up with topical ointments, even neosporin and it continues to break out. It’s different than razor burn because it’s almost like pimples before they become scars.

I don’t wear tight clothing that often and I don’t know why it’s only one leg like this. It’s itchy and some of the spots are raised and others are just like bright scars

Any advice? Thanks