How much would it cost me if I were to get a keloid surgery behind my ear?

See the doctor first. You need to find a good plastic surgeon who has experience in treating keloids.Myself as a practising plastic surgeon will never remove keloid on 1st session.Iusually treat them with injection of locally acting steroid(triamcinolone acetonide).Many times keloid shrinks and may not need surgery.But, you needseveral sessions of injection.So, go and see a plastic surgeon.