Can't get it up one year after circumcision

Ok, here goes, I am 27 years old, because of exima, I had to get a circumcision about a year ago.  I had bad dry skin and cracking on my foreskin.   After the surgery I was with a girl who was not extremely attractive, but not terrible and I had no real problems getting it up and keeping it up, even after drinking.  I am now seeing 2 girls and am having problems keeping it up.  One of the girls I have problems getting it up.  
With the girl I can get it up for, she ia a very attractive girl and she is good at foreplay and really trying me in the mood, but sometimes if we are changing positions it'll go down and, once that happens, it takes a lot of time for me to get it going again.  Also, she is young and keeps asking why isn't it hard, and get it up!.  
The other girl doesn't do anything for me, she had been raped earlier in her life and doesn't do much in the way of pleasuring a man.  I have trouble getting it up even while I am orally pleasuring her, which I love to do, and she ia fantastic in that department.  I know this girl has cheated on her boys a lot, not that I have much room to talk in that area, since I have some action on the side right now.  
I thought this could be psychological, but I have excepted the second girls whorishness, and she doesn't pressure me to perform.  I honestly know, that I could never settle down with either of these girls.
The other thing is I smoke about a a pack a day, drink a lot of energy drinks and drink a lot at night.  Another psychical issue is the sides of my penis just behind the head crack and split now and its pretty painful, I useneosporin constantly to try to heal this up,  but er are heading into winter now when my exima is the worst.
Please help me this is a huge embarrassment.  Thank you, mike