the pain may be due to injury
to the gum or bone during deep cleaning. Alternatively, it may be due to infection in the bone. There are also chances that some tooth structure i.e cementum has been eroded due to improper subgingival scaling resulting in severe pain
.please ask the patient to go for a dental OPG to see the cause . Please prescribe powerful analgesics like Ketorol and Aceclofenac
along with antibiotics to give relief till the cause is known and treated. Take care!