Did you pour the dregs on top of the head? Or was the head just "rocky?"
If you poured the whole bottle, especially at two weeks old, without stopping before the sediment came out, then you just wound up with a layer of yeast on top of your head.
Might make you fart a little, but other than that you're good.
If the head is clean and you left a little beer (and sediment) in the bottom of the bottle, but your head is sort of rocky, that's okay.