I tried everything on the remedy page here (and then some) during more than 10 years of recurring anal fissure bleeding and pain. Some remedies worked partially and temporarily and some not at all. Probably the best of those already listed here was botox, but that only worked 90% or so for about a year.
The first thing that has worked perfectly in the long run is fully ozonated olive oil applied to the affected area and further inside. I've been six months without any bleeding or pain even after the occasional constipation/hard stool. The ozonated oil (which is a thick white paste) feels good as it's working, and the fissure site healed up completely within a couple of days and stayed that way. In addition the muscle has relaxed and become much looser. I tried making my own oil with an ozonator, but that took over a week and nearly burned out the motor. I found it easier to buy premade fully ozonated olive oil online. I hope others will find the same total relief I have found.