My story might not be so comforting and I apologize. I had one of the worst episiotomys. I am 5'1 and was only 120 pounds, all baby when I delivered my first. He was 8lbs with a huge head. My petite little body had a difficult time pushing this baby out and I tore! The stitching was internal and external as well. Unfortunately, it did take a few months for me to heal. I couldn't do very much, and the doc did say it was the worst episiotomy he has ever seen. I have since healed, of course, but it did take a few months. Although I was afraid to look and see what it looked like, I can tell you it was not pretty from what I was told. They never did say it got infected. Everyone is different. I took very very good care of it every single day. I took a "sitsbath" and placed it on the toilet every day with mild soap to clean myself about five times a day. I would sit on it for about five minutes. I wouldnt touch it or used a washcloth. I would just soak my bottom in it often with warm/hot water. it helped! A midwife's remedy and it helped. it takes time, but I can totally understand your concern.
I had an episiotomy because I tore and I didn't have any issues like you are describing. I don't have any loss of feeling like that and my scar definitely didn't heal up like that. I would absolutely get a second opinion.
I did not have an episiotomy, so this is tough for me to comment on. A couple of thoughts though...I am almost exactly one year post c-section. I have talked to other women who claim their scar is almost nothing now. Mine is still red, raised, and ugly! I also have little sensitivity around the area. When I spoke to my Dr. she said that everyone has a different experience and heals differently. She was not concerned about the physical appearance, just that it is healing well. I guess that is (and should be) a Dr.s primary concern. The comment was made however that it wasn't the "neatest job" whatever that means.
If I were you, I might get a second opinion. Just have someone else take a look. Perhaps the Dr. that did it didn't do the "neatest job" if you know what I mean, and perhaps there are options to help it out. I do believe the loss of sensitivity is fairly normal, at least I would think so given that when they cut there are nerve endings, etc. cut through. But when in doubt, always seek a second opinion.