If it looks infected, you can contact your doctor.
I would get blisters and open sores from pumping. First, find ways to prevent it and to keep them from getting worse. Make sure your horns are the right size for you and that your pump isn't set too strong. I was told no more than 1/4-1/3 of the full power. You can lubricate your nipples to keep them from rubbing too much. To do this you can apply a little olive oil around the base of your nipple before pumping. My LC told me to do this and said it is safe for the baby.
To heal the nipple, I suggest trying a few different things. After pumping you can dip your nipple into a warm solution of salt water. This can help soothe, heal and prevent infection. You can also apply breastmilk and let it air dry. This has remarkable healing powers. Many people find lanolin helps. When it was really bad, I would also add in nipple shells. That are hard plastic shells that allow the nipple to heal by keeping all clothing off of it and allowing for air circulation.
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. MedHelp is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.