Oh no poor Mausie :( I'm glad he's all better! I actually know about cat acne, my kitten has it on her chin.. the vet recommended we clean the spot with an antibacterial gel every other day, so that it won't get infected and so far she's good :)
This is a gorgeous baby. Do you bath him? We had a cat this happened too. After the third go with it we began to bath her often. It never came back. They told us it was allergies. But there are no allery pills for animals. I am so pleased your baby has recovered well.