Seeing the image it seems to be a case of anal-fissure, still clinical examination will be more helpful.
Are you having hard stool? Do you have to strain during defecation?
You have to do Sitz bath with lukewarm water (sit in a tub with lukewarm water) 3-4times daily and then apply Anobliss/Escot ointment after every Sitz bath and before defecation.
Consider a Stool softener if hard stool present.
Next Steps
Visit a Proctologist or General Surgeon for better evaluation and opinion
Health Tips
Have plenty of oral fluids and high fibre diet