i say go to a vet. i would say that regardless with blisters because of blister disease but with this being so close to his eyes and brain, i would definitely be a little more cautious.
i had a boy who had blisters on his neck and i treated the outward signs. i thought he was getting better and then i came home one night and most of his skin on his neck had peeled off and he was sitting in a pool of his own blood. he died the next night after a trip to the vet.
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vonnie
***I have learnt silence from the talkative, toleration from the intolerant, and kindness from the unkind; yet strange, I am ungrateful to these teachers. Kahlil Gibran***