Help please help?! my little brother just got a ticked pulled off his head....?

Okay so my little brother (7years old) was playin wii when I spotted a tick not to big but not tiny either and it was on his head in his hair behind his ear. Well he's feeling sick now.. I don't know if its a weird coincidence but if you know if this is normal or somethn please help? Or what's some sympotms of some sickness caused by ticks?