Thanks for writing to us.
Painful lump anterior to left ear may be due to-Inflammation of parotid gland
Inflammation of lymph nodes/lymphadenopathy
A clinical evaluation of the area may help to rule out the condition.
Apply frequent hot/cold
Take complete course of antibiotics.
Avoid mouth opening too widely.
Chances of TMJ dislocation also has to be monitored.
Please do visit your oral surgeon for further reference.