Hallow Dear, The hard stools due to constipation has caused an anal fissure which has got infected, as you mention. First step should be to get relief from the anal fissure and get it healed. You may apply local applications like Practosedyl with finger to the legion after every motion and even otherwise also. This will help healing the wound and relieving you from the pain. Simultaneously, you have to get your constipation treated. Initially, try liquid paraffin at bedtime which will soften the stools. However, it should not be continued for long lest the risk of fat soluble vitamin deficiency. Get your stools examined for any evidence of Amoebiasis. If detected, you will have to undergo treatment for it. Metronidazole is an effective medicine for it. Consume lot of fruits, particularly citrus fruits like oranges in your diet. Avoid meat and eggs. These are constipating food articles. Regular use of Isubgul granules at bedtime with lot of warm water will help you get rid of constipation. Iron tablets taken during pregnancy are invariably cause of constipation. If you switch over to time released spansule form of Iron, it will not cause any constipation. I hope this helps you to find relief.