I only took half a pill of the hydrocodon with the m357 symbol on the pill
And I have to take a urine test tomorrow how would this work ?
I had a headache and a friend told me to take half when I mentioned that I had to take a drug test about an hour later her reaction wasn't so great
I need an answer ASAP

First off, Tylenol is good for curing headaches. Vicodin is for people who need it, hence the reason it's a prescription drug.

Secondly, was it specified as a urine test? If its for a job, they may do a mouth swab. Then again they may do a urine test. I don't know.

Third, if you drink lots of water and cranberry juice you SHOULD be fine, I'm not saying that you WILL. I took two vicodins before a job related urine test, and they said that they didn't detect them. I don't know if they didn't test for them, or what the story was. But mine were prescribed, so it wouldn't have been a big deal.

Either way, drugs are bad. Don't take prescriptions that aren't yours. And be safe. And good luck.