Anal fissure may be acute or Chronic.You need to observe for whether yellowish pustules you captured are just skin origin or from inside..
That means once they burst open they just emit liquid and become scarred which means confined to skin..
Or if continuously discharge or pus getting out of it..which means fistula..
So if second one is the case go for per rectal examination and MRI if indicative
Next Steps
Go for per rectal examination
Health Tips
Maintain good hygiene, Have more fibre diet and less non-vegetarian and spicy diet