It will be advisable that you get yourself examined by a Surgeon to know whether you are suffering from Anal Fissure
, you have mentioned are mainly used for piles.
It takes few days to weeks for healing of anal fissure.
Continue Sitz bath.
Use Nitroglycerine ointment for better healing along with local anaesthetic
Contiue with high fibre diet and take mild laxative after getting yourself examined by the surgeon.