Swollen arm from gardening work.

I did a landscape job few weeks ago and when I came home the sides of my lower arms like where the elbow begins were swollen, it went down by a lot, almost 90 percent but it's been several weeks and it hasn't fully gone down. When I stretch my arm fully I still see a little knot. I can notice it a little bit. There is zero pain now. It's just the look that bothers me. How do I fix this? I'm hoping it's not permanent and serious replies only. Any trollish replies are deleted immediately.