You can go to Thailand if you're from certain countries without a visa for 30 days and get a 30 day extension from the immigration office out there. Or you can apply fir a tr visa (60 days) before you leave from the Thai embassy In your country. If you do the latter and get the 60 day visa before leaving home you can still apply for a 30 day extension when out in thailand making a total of 90 days
An antihistamine would help. I've also been told to put a spoon in a hot drink for a bit and let the spoon warm up then place the back of the warm spoon on the bite and it takes away the itching 😀