Reaction to Peanut Butter?

Hi all,

I gave Noah PB sandwiches for the 2nd time yesterday and like last time today he has developed a very red bum (and cries his little heart out when I have to change him), however I've also noticed his 8th tooth is starting to (finally) break through and he was teething the last time we gave him PB as well which was a few months ago.

Is it a teething nappy rash and it's a coincidence or has someone else come across a reaction to PB like this?

TIA

I would say its teething as a reaction usually occours around the face/throat area, but as Emmi said try when hes not teething.