Tiny hole from seroma, second time. What could keep causing it? (photo)

Most likely thing going is on their is a foreign body(suture/something) that is under the skin in that area and the skin does not want to heal over the area bc it is collecting fluid. Discuss with your surgeon. 

Causes of recurrent nonhealing wounds can include retained foreign bodies.  Sutures are a common cause of this in abdominoplasty surgery.  Check with your surgeon to see if there may possibly be a suture or other foreign body that may be causing this.  Best wishes, Dr. T. 

You might still have a low grade infection that has shown itself only by a reocurring seroma. You probably need to go back to the OR, have the pocket irrigated well, and exchange your implant for a new implant.

It is unclear from your description why you are having persistent drainage. Check cx's for fungus as well. You might have to remove the implants and allow things to settle down for a while.

The obvious question was the second exploration operation drained with a drainage system for 10 days? If not you might consider placing a drain for a few weeks external to the incision, re suture the incision. The other school of thought is removal of the implant completely,. Wait for 3 to 6 months than insert a new implant again. Only in person examination allows that decision with you.