We had a guy in our band with the same problem. He put every band-aid (ha!) imaginable on it, and it worked okay for a while. Eventually, it was just too bad to fix, and he ended up replacing it.

I've heard of pipers using barge cement or aquaseal to repair seams with decent results. Not sure what your options are at the chanter stock. I've never had to deal with it, so I don't know how it works.

I play a hide Gannaway, so seam issues aren't too much of a concern.

Good luck!