fireshadow

I found that using Saniderm on my healing leg helped a lot with the blood-rush feeling. Obviously, take your artist's aftercare advice, though. (The downside is that a lot of liquid collects under the Saniderm, so if you do get the OK to use it, you might have to change it a couple times to avoid leaking). Putting a bag of frozen peas on there helps, too. I basically tried to remember RICE (rest, ice, compression, elevation).
I just rock the leg hair over a healing tattoo for about a month.

I don't know if my input is as helpful as you're looking for, but I have my head tattooed and I shave regularly. By regularly I mean every two or three days. I shaved the day I got tattooed just to speed up the process so my artist didn't have to spend time doing it. After that I waited three weeks just to make sure the tattoo was fully healed before shaving again. As for itching I just dealt with it. It was only bad the first four or five days but the itch goes away. And don't worry about the hair growing through the tattoo, that's just normal. Just let your body heal before shaving again. Any tattoo I have that required more than one session needed to be fully healed before moving onto the next session. Shaving or waxing can really affect your new tattoo in a negative way since it's still a fresh, open wound.
And I think that might be a reason you suffer so much pain. 11 hours in one sitting is a lot of trauma to the skin. The longest I went on my lower leg(below the knee) was 3 hours and I had similar effects when I stood up or walked around. So I can only imagine how bad it was with a such a large tattoo.
I hope everyone's input was helpful! And good luck on your next leg tattoo!!

I wouldn't subject your skin to something harsh like nair or waxing for at least two weeks prior either. Your skin needs to be in top shape.