Regarding your first question,it could be Allergic or Irritant contact dermatitis
and you need to see a doctor to have a live look and proceed further,but for now on you can apply white petroleum jelly on the patches.
Secondly i am not sure that is the swelling in one or both the legs?
It need a detailed history and discussion to clear things up and unfortunately its not a question answer session so you have to see your GP. I canot comment further cos of a very brief history i am afraid.
THANKS VERY MUCH