[dentist90]

Serous fluid perhaps? Just clear tissue fluid. But that does look like a dehiscence that may not close spontaneously. It’s good to have drainage initially to avoid swelling and this will probably heal from the inside out, but it might leave a noticeable scar. Like Noah said, if after a few weeks there is still a deep defect removing a thin layer of skin on either side and resuturing should get primary closure.