use an 16 or 18 ga needle/syringe to see if you can pull stuff out of it. You can make a small cut with a scalpel or sharp blade at the bottom(low end) of the swelling to allow it to squeeze out, leave it to allow drainage.
I have no experience with La200, Nuflor or Draxxin would be my choice.
Ya'll do seem to have a harder time finding meds up there, makes it hard to treat correctly sometimes I'm sure.