Bitten by some sort of insect on my arm. it stung badly and was extremely itchy, red, and swollen but went away in a few min. a week later developed a dark scaly rash, dryness, and red spots with swollen lymph nodes on the armpit. what do i do?

You need to go to the ER for treatment. We can’t know your diagnosis without seeing the kind of insect that bit you. However,big lymph nodes mean that there’s either an infection or a reaction to the inflammation that it caused. It could be Lyme’s,Rocky Mnth.Spotted fever,etc. or a local infection like Staph or Strep.etc.You might have an insect part that needs to be removed.