Fissure is characterized by tear on the inner mucus membrane of anal canal and and it is caused by passing the hard stool from the anal canal.
Actually this hard stool during passing the anal canal compressed the inner mucosa tear so that's blood during passage of stool is come out so most important precaution you should take care like drinking sufficient amount of water so that your stool will we loose , not so hard so tear against anal canal is not happened again and slowly slowly can be heal by proper medication and lifestyle modification.
You should take consultation for proper diagnosis and treatment.
Next Steps
some test are also required like colonoscopy , anoscopy sigmoidoscopy and some blood test.
Health Tips
you should follow good lifestyle like taking sufficient amount of water and taking less spicy and fatty food .