Help! This blemish(?) has been on my sons cheek for 8 months now

I’ve sent the pediatrician a message with images. Please no hate for not inquiring sooner I already feel terrible about it. (Image in comments) Redness around it comes and goes, it first popped up looking almost like a scar from a blemish, 2-3 weeks after a rash he had all over his body had cleared up (ped diagnosed it as erythematous macular rash) and then it got red, sometimes it forms what looks like a deep white head but it never surfaces, it gets pretty red around it on his cheek and then the redness goes away and it goes back down looking like more like a scar. This happens over the course of a few weeks-a month or two and seems to be a cycle. Has anyone seen anything like this before?