Yep, Harry got addicted to Bitter Apple too....
I have read on here (I think!) that men's stick deodorant is another deterrant - I haven't tried it so not sure if it works
Harry grew out of that phase all of a sudden.
I always found distraction to be the best cure (as with skin kids) - try offering a nylabone or bullystick for chewing on instead? Good luck! Sally + Harry x