Since you know you cleaned two of the holes, you can assume that you cleaned the outer part of your ear normally. This is sufficient and there is no need to immerse again even if you didn't clean the other two piercings thoroughly.

In general if a woman has doubts about her chafifah while still at the mikveh, she should clean the questionable areas and immerse again. However, once she has returned home, and especially if she and her husband have already had relations, many (but not all) chatzitzot are treated leniently and there is no need to reimmerse.

Please feel free to get back to us with any further questions.