I regrettably got a corticosteroid ing into my left adductor tendon 2 yrs ago-now the fat is gone and it is weak/shrunk. is this permanent?

Yes and no: The fat being gone is likely permanent and can be a side effect of cortisone injection but the weakness is usually from muscle atrophy which can be strengthened. If the fat loss is a concern a plastic surgeon may be able to inject new fat into the area from somewhere else on your body.

Yes and No: The fat being gone is permanent, although some cosmetic surgeons are having some success with fat transfers. You may want to consult a specialist. As far as the weakness, see your doctor about a referral to physical therapy. They should be able to help return the strength and flexibility to the area.