First of all if you are using commode toilet, then use toilet step stool, commode toilet is unnatural for humans, Western toilet increases constipation. Since Constipation is a bigger factor behind sentinel tag & Fissure. avoid constipation, eat fiber food & if you can remove this sentinel tag without surgery with kshar sutra.
Next Steps
Go to nearest Ayurveda Kshar Sutra Specialist Doctor or consult me