Hello Maggie, We live by the sea at Bournemouth, and we often go for a walk along by the sea, and sometimes take our sandwiches for lunch with us, one very warm day last year, my daughter, husband, and two grand children and me ofcourse were sitting by the sea eating our lunch, when I screamed out in pain. I had bitten my sand which along with a pesky wasp, the pain was dreadful, and like you I started to swell, my daughter a nurse consultant, immediately opened her ruck sack and gave me a Anti Histamine tablet, which brought almost immediate relief, one of my German Shepherds was once stung by a wasp on her mouth, and when I rang the vet, he said if I had anti histamine in the house to give her one, which I did, and it stopped her muzzle swelling any more than it already had, the motto of these stories is like me always carry anti histamine. Best Wishes Elaine