Well my older cat who is 10 had some teeth taken out around 3 months ago and doing well. On noticing her upper lip she has a small pink mark there. Its where her bottom canine occasionally gets bit caught on there. Not sore she still eats very well and not weeping. I asked her old vet why he didnt sort this out when she had her operation he never got back to me. So in a few hours going to a new vet today for a opinion. Anyones cat had this problem. Tia