Bites on baby that won't go away! It scars.

My 16mo son has started to get these bites outta no where. It started when he was 14mo.

It starts off as a red patch (without head), progresses to become a swollen and hardened lump. Eventually a blister-like head will appear. After it dries off, it just remains like a hardened & raised scar.

Been to the dermatologist, have been using Frucicort (doc prescribed as a safe steroid cream) for baby. He said baby is getting an allergic reaction to the bites. Can't determine what these bites are though. Suspect to be mosquito bites... but he has had normal round mosquito bites before and they subsided w no issues.

Heart ache 💔 to see his baby skin scarring so much. Nt sure what else to do now. Anyone experienced this before? — feeling sad.