How to get rid of a lump remaining from a cauterization of a vein?

Aggressive thermocoagulation can cause lid retraction in very rare cases. This can cause undue dryness of the eye. I recommend that you see an ophthalmologist or oculoplastic surgeon for guidance. 

It sounds as if the vein clotted and now you have developed some contracture from the scarred vein causing the lower lid to retract. You should see an eye surgeon or plastic surgeon or return to your original treating physician. Surgery may be the only option.