[NEED HELP] Transparent glossy polygon shape

Hey Guys,

can somebody point me in the right direction please? 

I'm trying to recreate the red merked shape. Use transparency is clear to me, but how can I create the white edge. is there something like a workaround to create these shapes? 

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SOLVED

USED THIS WORKAROUND. It was really easy 🙂 

Thanks for any hint or advice 🙂 have a nice sunday 

This is my finished type 1 diabetes glucose watchface