Hi there ~
It is a nuisance to have bumps on your legs that itch and have swellings that appear constantly. One reason could be contact dermatitis
which is due to walking in grass or other substances that you are allergic to. Allergic dermatitis
is quite common and is easily treated with anti-allergic medications. I hope this helps. And yes, if it itches, do not scratch, you are only going to make it worse. Take care and have a nice day !