my shih tzu apears to have a shampoo allergy, every time he is bathed he comes up in bad sores which he wont stop biting, and licking, i have tryed bathing him in savalon and it appears to of worked, although he is still coming up in a few places mainly at the base of the tail, on his side, and on his head, has anyone got any idea of how to allievite it please can any one help me many thanks