Suggest Remedies For A Painful Lump On The Lower Left Jaw

My 11 year old son has a painful lump on his lower left jaw in front of his ear. He began to notice it yesterday. At first it was close to his earlobe but it seems to have moved forward slightly along his jawbone. I felt it and it is a hard, pea sized lump with some swelling around it from what I can tell. He said he did notice an odd taste in his mouth, sort of like blood, yesterday. His teeth are not loose. It hurts when he opens his mouth though not necessarily when he chews. I gave him some ibuprofen and he said it helped the pain. He has allergies but hasn t been taking his Zyrtec lately. As a baby he was prone to ear infections and had tubes inserted in both ears at about 2 years old. Is this urgent? Do I have him seen by a doctor or by a dentist? I appreciate your insight. Julie Smith