How should one manage a non-healing wound with tunneling at the site of a cyst excision on the back, now two months postoperatively, with negative wound cultures and in the context of a self-pay patient?

"Non-healing wound" suggests persistent granulation tissue or similar exam findings, which in the context of tunnel formation at the site of follicular cyst raises my concern for hidradenitis suppurativa (if only a diathesis toward follicular occlusion in a patient without a history of HS). If there...

Tunneling may be due to epithelialization of the site and/or cyst wall remnant or foreign body reaction, such as to trapped hair, with local dehiscence and then epithelialization.

In all of the above, I would open the site and remove the tunnel/epithelialized site, and foreign body reaction material...