18M Sulfuric acid burn?

I was in chemistry a week and a half ago and we were performing an experiment. I had removed my gloves, because the experiment was over. However, as i was cleaning up, I spilled some 18M sulfuric acid on my finger. Let me tell you, IT BURNED. I didnt tell my TA because it was time to leave, which I know was a bad idea. I ran it under for about 10 seconds, which is probably too short of a time. Its on my left pointer finger. Its difficult to describe how it looks. It is painful to the touch, and it hurts a lot more in cold weather or in rain. It is surrounded by a pinkish red color and then there are like little specs of brown that look like scabs. However, they arent scabs they are really deep. Is there any treatment that i need to follow up with? I have done some research and it says Sulfuric acid is the most dangerous when it is above 1.5 M, and this was 18M. Just let me know of anyway to get rid of the pain and or keep it from being infected. Just so I know that it isnt already infected, how will I know if it is infected and what are the implications of this?