Burn on my foot..HELP?!?

About 3 days ago, I was using a sparkler (the firework thing, ya know?) And a chunk of it fell off, and i stepped on it. I cleaned it, put neosporin on it, yadda yadda yadda. NOW, it looks like it's healing well, BUT I keep getting shooting pains in and around the area of the burn. I have been walking on the side of my foot because I don't want to irritate the burn. Is this why I'm getting those pains? If not, why am I?