As you said valerian does stink a bit. It's not really all that unpleasant though.

The active part of the plant is the root. It is generally ground into a powder and taken in capsules. You can also make a tea from a coarser grind. (this is what I do)

Valerian creates drowsiness. This is something that FMS sufferers need as their sleep system is generally out of whack.

I (for example) may be dead tired and very sleepy but it is still hard for me to go to sleep as I don't get drowsy without some kind of aid.
It's horrible to need sleep so badly but to lay there in pain with your mind still awake.

Valerian delivers the needed drowsiness allowing me to go to sleep.

It can cause morning drowsiness as well if taken too late.

The principal drawback is that it is slightly toxic and this toxicity accumulates so it is best to alternate valerian with other similar products such as melatonin, St Johns Wort, kava kava, etc.