Kitten Paws Problem

Question
Hi,
A month ago, i noticed that my 7 months old cat had his paws looking like if they were real dry, so dry that they were cracked. I took him to the vet and he told me my cat might be lacking some Omega3. He prescribed the oil Omega3 MIrra-Coat, to give it to him once per day, and also Urederm Lotion to apply it on his paws 3 times per day. Even though, my cat was wearing one of those plastic cones, he would manage to lick his back paws. Is distressing cause when it looks its getting a bit better, he gets again the blisters, the blisters dry, and the dead skin falls off, and again he gets blisters, and same process...
They also sent some of the dead skin to laboratory to test for fungus, but it came out negative.
Anyway, there wasn't really an improvement and went back to the vet. He asked me to change the litter from clumping litter to crystal litter, cause maybe he was allergic to it. After all this, my cat still has real dry paws and him trying to find a solution cause i know its hurting him when he walks.
Please somebody help me. I can send pictures as well.
Thank you so much in advance.

Answer
That is a weird case.  The Omega 3 fatty acids may take 30-45 days to work, so keep up the lotion until the fatty acids can get a chance to work.  If all else fails, ask for a skin biopsy and histopathology of an affected area on the foot.  It could be an autoimmune type of disease.  Has the vet tried any steroids, yet?