The hot water stopped running through just one bathroom faucet. (It's a two-handle system). I turned off the hot water supply line valve under the sink and removed the valve inside the handle. But even when I turned the supply line back on, no water came out of the handle. There's a small, short-lived drip from the supply line valve when I open it, but it stops after I shut it. I've never seen anything like this. Any ideas?