I Was Stung By 2 Bees/wasps On The Hand In

I was stung by 2 bees/wasps on the hand in Thailand 2 days ago. I took one anti histamine each day but today the swelling has reached my wrist. What to do? I have to admit I have scratched the hand (often) as its so itchy & last night made an ice pack for said hand but it's worse today!