Does botox injection for anal fissure cause much pain?

Not much but needle : It will be painful but it depends.They use a very fine needle and that reduces the pain compared to bigger needle, but there will be pain.

Same as injection: This medication is injected in the area to be treated. Discomfort would be similar to any other injection.

Well tolerated: Botox injections are usually well tolerated. They are administered with very small needles.