Your post op condition is extremely unusual. Cone beam CT imaging study is warranted to rule out root fracture .
Taking ibuprofen 200-400mg and acetaminophen together and around the clock, every 6 hour can yield maximal pain killing effect. Moreover, if there is evidence of infection and amoxicillin is not effective after 72 hours , switching to second line antibiotics is warranted.post op pain of crown lengthening procedure rarely lasts more than 48 hours. Oral rinse if chlohexidibe twice a day is generally recommended for oral surgical procedure.lastly, cessation of cigarette smoking is strongly recommended.