
Chris
Is this lump, rather like a fluid filled water lump/blister ? If so yes it will be the Mucin that makes and forms the wrinkles in the Sharpei breed. A lot of the breed can suffer from it, several of mine have had this from being youngsters. Can be a single blister or a cluster of tiny blisters.
As long as it isnt bothering your dog, I'd just leave it alone, sometimes they can burst on there own, if so just wash the area with a saline solution, and just watch for any infection, but this is very rare as long as the area is kept clean.
If it does bother your dog, just get a clean disinfected sawing needle and gently insert it into the water/mucin blister and pop it to allow the excess mucin to flow out, clean area as above, and everything should be just fine.
Please join the group, so the members will be able to advise you further if need be.
Hope this helps