Hello You mention problems with constipation and rectal pain. It is important to drink plenty of fluids to prevent constipation and dehydration. In fact it has been shown that people who drink more water are likely to lose weight. Also, it is important to have enough fiber in the diet (fresh fruits and vegetables) to help with bowel movements. A high fiber diet has also been found to help with weight loss. Constipation can cause hemorrhoids and anal fissures or tearing from the pressure caused when bearing down. Various creams can be used that have the ingredient hydrocortisone. For exterior irritation regular petroleum jelly may be used as well. You can also try glycerin suppositories which can help you move your bowels. Best regards