If you really can't move your arm because of the sting, and there is pus, the best thing you can do to yourself is go to the Emergency doctor. You can take an ibuprofen if the pain is too hard.
B) Becoming aware of your own reaction to it, is the first step. From there you can take steps to handle your stress like catching up on missed sleep.
I believe you are free to hike without training.
D. Hike
Are there answer choices? If not I think the answer is oxygen.
