Oh, this sorta stuff can be messy and requires some patience! Use the reduction brush. Make sure you got it at the right size on the right place for it to have proper effect. Once you reduce the geometry there, use SMOOTH to soften it back out, then continue with the reduction brush. It can be a hairy process, but usually works fine.
Also, hit 9 to see what's really going on there. It will only show half of the model then. You may reach certain parts better with the brush, but it's not guaranteed, as it won't reach through where the other half would be in the way. Kinda stupid, I know...but eh... well, it's better than nothing to at least be able to see more.
Rest assured, though, you CAN in fact fix it. Little tip: Always be careful with the inflate brush, which is the most dangerous one in all applications of that kind, including zbrush. Naturally I don't know, if that's what was causing it, but it's a common mishab that could end up that way.