I cant be around the guy i like without severly blushing! i shake and start to studder!....?

An employee i work with has a son who i like who tends to stop by my work sometimes to see his mom. well everytime he walks in the room i blush so bad my face, neck, arms bust out into this horribly red. i burn up and cant talk. im normally very shy so its very commom for me to blush but i dont want everyone in the room to know that i like him because of my bright red face that appears. its so horrible and it keeps happening. ive tried saying things to him but it only makes things worse because i blush so bad and its so embarrasing. i dont want to feel like that. any advise? and i might mention hes very very good looking and i dont think his girlfriend appreciates my blushing around him either but i cant stop! I reallly need to get rid of my blushing somehow