I have a golden retriever and have just had him groomed
He is licking a spot on his tail by the rectum where he
got razor burn. Does anyone know what I might do for Him
as he is so uncomfortable.

Poor, poor baby.

Is the area open or draining? If so, I suggest contacting your vet immediately. S/he may want to give you some antibiotic cream to help decrease the risk for infection.

If it is just raw and irritated, cold compresses work very well. He should feel better in a couple of days. I won't dare tell you to give a pain reliever but check with your vet and ask what you can give if the pain is causing major discomfort.

If you have an aloe plant...it works wonders as well for burns.

Hope this helps and sorry I couldn't offer more.