The oter day I went outside,with no shoes or socks,just to get in the car.While I was walking I got a pain in my heel,but I ignored it,thinking I just stood on a stone.Now,this morning my heel REALLY hurt and I looked at it.I noticed a small red stain on my foot.I recogized this as blood,and deeper in the blood,there seem to be something stuck in it,I told my dad,he said it's a bruise,but I'm really worried.Can someone help?

I'd show it to your Dad/Mom, explain what happened, and ask to have it checked if it continues to bother you. It could be a piece of glass or something else you stepped on.