Red lump on tragus peircing?

ok so ive had my tragus pierced for around 3 months now and over the past few weeks a red lump has appeared at the front just behind the stud. its not painfull if i dont touch but is a bit sore when i lie on it or move the stud. ive continued to wash it twice a day with salt water but it hasnt helped. any ideas what it is and what i should do about it? thanks :)