Weird nipple. Picture included

The only thing I can describe it as is a Scab. They have been on there for I want to say 4 years. I've never had a doctor say anything about it when they do my breast exam. But sometimes it rips off and it's very painful. I've been putting petroleum jelly on them after showers and one seems to be getting better. Does anyone else have nipples like this? I do have two children and tried to breastfeed but didn't for more than a few days