Well, without actually seeing the mount, there could be a few problems. One that comes to mind first is dry preserve. Did you get a real good deal or should I say did you pay less than other taxidermist in the area? Most DP mounts are cheaper, at least in my area. It could be a pickle tan, although I have never had it happen to me, I have seen it in other mounts that weren't properly neautralized. I am not knocking anyone else's work but try taking it ot a reputable taxidermist or even the one that did it and see if they can fix it. A lot of times it can be repaired, usually I use epoxy sculpt or modge podge to fill the crack and rebuild the nodules. Some others on here might be able to help with other info. Hope it helps