Sora had that recently. I cleaned his chin everyday with witch hazel and it cleared up in a few weeks.

we started using glass dishes instead of plastic and it cleared right up! Looked it up on internet and that's what they suggested. Never went back to plastic and no problems since we switched.

Yeah, that's what we're going to do. Washed their beds, getting new bowls tomorrow, and we've started cleaning her chin.

Yes, I forgot to mention I cleaned her chin with warm wash cloth. Didn't take long for it to heal.