Welcome to HCM.
I think it might be two different entities. Sore throat
might be due to viruses which are the most common cause of it, most of them are self limiting and require only symptomatic treatment. I advice you to take the antihistamines, along with that i advice you for salt water gargling 5 to 6 times day.
Regarding rashes on leg, it is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided.
I think it might be due to contact dermatitis
, I advice you to wash the area with running water and apply any over the counter antihistamine cream.
If the symptom persists or severity increases i advice you to see physician.
Hope I have provided the information you needed.
Wish you good health. Take care.