How can a thin walled cystic lesion measuring 16(trans) x 10(cc) x 16(ap) mm in left sublingual space, with evidence of thin inter septations be treat?

Need tissue: Ideally a fine needle aspiration should give as an idea about what the cause is. Without knowing what the etiology is, it will be hard to treat, unless this is a common condition in your country and trying to treat first based on your physician experience and comfort level might be a viable option. What are you taking the Ivermectin for?

See your doctor: This sublingual cyst of this size may be bothering you , but it usually does not interfere with talking or eating. most probably not infected , it is benign growth , but you should see your doctor who can advise you for treatment, -removal of cyst.

Depends: What caused it? Inflammation-infection? Malignancy. Many cysts can be excised, unroofed, drained, BUT diagnosis - biopsy may be required?