How long can you let your Vampirism... build?

You know, if you don't feed after a set amount of days your powers increase.

How long before you are "obviously" a Vampire to the regular guy on the street?

If you get that bad... is there a way to bring things back under control so you can start mixing with reputable society again?

Thanks in advance.

Az

If you didn't get Dawnguard, you are hated on Stage 4. However, with DG on, you get attacked if you're using your Vampire Lord form.