Talk to Ent Specialist on Bone Swelling Behind Right Ear

Today I just saw this bone protruding behind my right ear when I was applying oil on head. Haven't noticed it before so cannot tell from when it has started to appear. But it was not there until recently. It's kind of hard to touch and feels more like a bone protruding rather than muscle swelling. No pain, no redness. No ear infection, no pain. Just had flu last week which has now subsided. I feel moderately blocked sinus n nasal congestion during flu. Too Kestine once daily for 3 days and nebulized with plain water only. What this could be? Will it go away of its own? See pic and suggest.