Hello Welcome to health care magic Thanks for your query. Most of the insect bites are local reactions and if the string sticks on to the place it should be removed first. Basically the place should be cleaned by water and given cold compress. Do not pinch or squeeze the blister, because it might further spread. If possible, use an adhesive bandage (plaster) to protect the blistered area. You can apply calamine lotion in the blistered area which will decrease itching sensation and further allow to heal. If the itching sensation persist you can take Tablet Citrizine 5mg once daily before sleep on night time for 3 days. Consult dermatologist and take further suggestions Wish you a good health