Ouch.. I need your help??

Okay, so I recently burned my arm quite severely on a tray out of the oven. I ran it under cold water from about half an hour but it still boiled and burst. Its started to scab over now but its still quite sore and is very hot to touch..

My question is how can I prevent scarring? Its in a very noticable place on my wrist and I really don't want scarring to occur..

Thank you for your help!