Dog has Flea allergies chewing till he bleeds

Question
Hello,
I recently went on vacation to see family and my dogs flea and tick repellant had just worn off at the middle/end of the month and he got fleas on him. They were not really bad but he has an allergic reaction to them and he started to get bumps and rashes. He also started to chew himself raw on his hind end and the base of his tail. We gave him a bath for flea and ticks and even gave him his monthly dose of Anti-flea medication. It was too late though, and now he has no fleas but he is still chewing. I don't know how to make him stop! We have a muzzle that we use so he can't chew but when we take it off so he can eat/drink he will slink away and chew in a hiding spot and make himself bleed. I really need some help to make him stop chewing! It breaks my heart to see him like that.
I tried looking online to see how to stop the chewing but all I seem to find is people who's dogs have food allergies and that they need a change in diet but that is not my case.


Thank you.

Answer
Flea sensitive dogs need to be started on corticosteroid medication to relieve the itching and self mutilation   YOu will need to take the dog to the vet for a shot usually, then you can follow up with tablets.  It can take up to 30 days after the last flea before they can go off the medication without having a contuinuous skin reaction.