Suggest Cure For Insect Bite

I get severe bites from all insects. I have only noticed this over the last 10 years or so - since I was diagnosed with hypothyroidism and I take 150 / day Thyroxine. Is this the cause, I believe it thins blood but does this make me 'tasty' food for all insects. The bites become itchy for a day or so then pink then purple and very painful leaving scars. A couple of years ago I had 33 mosquito bites on my legs and had to have a tetanus at the hospital. Horrendously painful and scarred. Do you have a solution and is Thyroxine the cause. Please help - I am afraid to walk on grass or go near plants. Kind regards,

Julie