Just some quick thought - ninaandbean, it sounds to me like you have an anal fissure. That's what I have. Pile suppositories and Anusol etc didn't help one bit for nearly two years. I just recently had it properly diagnosed during a scope for my insides. I actually had to ask the doc to check, and he was shocked that that's what it was. Everyone thought it was haemorrhoids! Anway - here's what I've been using, and it's helped enormously. However, I really have to keep after it - one hard stool and I'm back to square one:
Lactulose, 5 - 10 mL per day.
GI -Encap (a supplement made by Thorne Research) - one with every meal.
Modified Citrus Pectin for fibre (made by Selekta) - four caps, once a day.
That keeps stool nice and soft so it just sort of slips out, rather than forcing past the injured sphincter. (A fissure is basically a tear in the anal ring. The worst is that it has no time ever to heal since most of us have a poo at least once a day.)
The reason I was prescribed Modified Citrus Pectin is that my friend who is a naturopath said that using traditional fibre just bulks up the stool which is NOT what you want - you don't want the anal sphincter to have to stretch too much until it's healed. Stool needs to become the consistency, roughly, of toothpaste until the fissure has healed.
The other thing I've found extremely helpful is changing my position while pooing. My fissure is posterior (on the tail bone side of my bum, rather than the vagina side). So if I'm on the toilet, I bend forward and put my hands on the floor in front of me. That seems to take the pressure right off the posterior part of the anal ring and it doesn't hurt to poo. I don't know what would help if your fissure is on the front side, though.
Apologies for the extremely graphic nature of this post - I've started to call all this unwillingly acquired knowledge "my degree in poopology". But there's no point in being delicate about this, any useful info simply needs to be spelled out.
crje, I had the same as you re the labia. It was my right one that was cut for the epesiotomy, and it developed a huge haematoma. When it healed, it left my labia looking like an elephant ear, with a cut toward the back. It used to roll up all the time and was extremely uncomfortable. Plus, the cut through the labia was never repaired 
. So this past November I had it fixed. I went private for it, as I was told that, even though the situation was causing my physical pain, it was, sadly, considered cosmetic, and I'd have to wait roughly 18 months to get it done under our version of the NHS (I'm in Canada). So I said, bollocks to that, and went private. Best money I've ever spent on myself, although I have to say the recovery was tougher than I thought.