My Kitten has a sore bum

Hi, I have a nine week kitten, she has had bad diarrea due to diet change, I put her on the right diet now and the poo is improving, but she still has a sticky, yucky bum and it looks red and sore, I would love some tips on what I can do to help her feel more comfortable, and the pooey bum is driving me mad. :queen:

If her bottom is covered in diarrhea remnants, use a baby washcloth or an unscented baby wipe that you have wetted with warm water and gently wash her (no soap) until she is clean. If there are more stubborn "cling-ons" clip them off using baby scissors (the kind with round points).

what was she eating>and what is she eating now.