Suggest Treatment For Hard Mass Behind The Ear

I recently noticed a hard mass behind my right ear. Its is located under the skin, and appears to be attached to the cartilage. When pressed upon there is no pain, it is causing the skin in that location to appear slightly blue/purple. Appears to have grown slightly in the last two weeks when first noticed. No allergies, no recent viruses or infections. No new or recent injuries to ear or piercings. One year ago there was a mole behind same ear that ended up getting larger and then scabbed and just fell off leaving a slight crater in the skin. Should this lump be something I should be more concerned with?