Hey!

Hopefully this makes sense.

I've been doing the quests for The Companions, and I started The Silver Hand.

I can go into the Underforge, I can drink from the Blood pool, and the screen goes black. I am outside of the Underforge, and there are no people around other than guards. I cannot turn back into khajiit, and I cannot get any further in the quest.

I've tried to manually advance the stages of the quest, but it will not turn me back into a human.

Has anyone else had this problem? If so, how did you fix it?

Just let the guards attack you. When your health is depleted, you should be knocked unconcious and wake up in human form (if I remember rightly!).