Injury While Walking On Gravel, Knot Under Toe, Painful. Any Help?

Roughly two weeks ago, I (temporarily) injured myself when walking barefoot on a gravel road, then, again on the same day, when stepping on an extension cord. There was minimal pain, and it lasted only a few seconds after each incident. Now I have developed what appears to be a knot under my second toe on my left foot, where I had previously injured myself. I avoided heavy use other than walking, with little improvement. When I did see some reduced pain, I thought to inspect it, and felt the knot still there, so I proceeded to massage it out...bad idea. The pain is now back! I began feeling the initial symptoms a day or two after my injury. I d appreciate any help you can provide.