My testicles used to be hanging low now they're close up now. i accidentally hit my testicle with the back of my foot and i think that caused it. should i be worried?

Heat exposure can increase testicular sagging & cold exposure can make them tighten up. If your scrotum looks & feels normal and you have no other testicular symptoms or abnormalities, I don't think there's any problem. If you still have concerns, see your physician or a urologist for evaluation & advice.

Testicles hang high or low normally depending on weather, temperature etc. Yes your accident probably did it. No worries. A support underwear is helpful