I'm currently a stage 4 vampire in Skyrim. As soon as I try and sneak into a town to feed, I get spotted like a kilometer away, even with an invisibility potion. Nothing seems to work! I don't want to make a new character since I'm a pretty high level. Is there any way I can look for a place to feed without them noticing me!?
I haven't played vanilla Skyrim in a long time, but I'm pretty sure you can feed off bandits and so forth in the wild before entering town. You might have to kill off most of the camp, run away, wait until the bandit "resets" to his normal routine, then wait until he's asleep. Nom nom nom.
Edit: this page on the wiki says
Dawnguard removes this penalty and people will treat a blood-starved vampire like any other person.
I'm guessing you don't have Dawnguard or you wouldn't have this issue. Installing Dawnguard could be a solution if you want to buy it.