is it possible to suffer any injuries that arent immeadiately obvious?

i fell in the street on friday and smashed the top of my skull into a concrete doorway and it still really hurts. an immediate lump appered, which has gone down, but not away. it feels like theres a small dent in too, but i might just be panicing. i am NOT suffering from a headache or anything tho.

thanks dr. dis.