It would be best for you to ask the original surgeon who did your hernia repair surgery about this. Only he or she really knows exactly what was found at the time of surgery and what was done to repair it. Thus, he or she will be best equipped to provide you with the safest recommendations. Piercing the lower part of the umbilicus is not the usual place that piercings there are done, and this is because the tissues are normally thicker and may not heal as well. Piercing of the upper umbilicus began most likely because most women have a thin "hood" of nothing but skin over the top of the umbilicus, and this lends itself well to simple, usually safe piercing. This is yet another reason why it would be best to run your intentions by your surgeon. Good luck.