I am a 19 year old male, and I had an LIS + Ulcerectomy about three weeks ago. In the first week after, things went well. I had no pain with bowel movements, and no pain in general.

About a week afterwards, I was going up the steps and afterwards I felt some pain. Almost as if I could feel that the wounds had been stretched. The first two stools after this hurt, but then got normal. No pain.

Yesterday, after my third week out of surgery, I had an extremely hard stool. The tip of the stool was very hard and I could feel my muscles spasming as I was going, but once I got past that the stool was soft and I didnt have any pain.
However, the rest of the day was miserable. I had an dull achy pain that I had commonly felt before my surgery. I was worried.

Today I had another BM and immediately it had that instant pain associated with any BM you would have with a fissure before surgery.

I'm worried that I have had a healing wound, opened it twice, and now the scabbed area has built up skin like before my surgery which caused painful BMs. I had an ulcerectomy to fix this.

I'm also worried that the muscle removed from the LIS will be growing back as I was assuming that the muscle flexes when you BM and afterwards while healing the fissure.

I have my check up in two weeks, and I'm worried my doctor will tell me it has not healed but that he won't be able to do anything to fix it.

I've had problems with this fissure since January, and if it doesnt get fixed with surgery, I don't think I'll ever get out of the depression and sadness this pain causes me.

Any experience with this?

Welcome and thank you sharing your experience.
Please try to avoid hard stools while you are healing, important to note that LIS makes condition for your fissure/wound to be healed. So even if you had retear and reopened wound, it should heal anyway.

Please let us know, how are you doing.