I had to replace a leaky shut off valve to my toilet and when I turned the water back on I have no pressure at the tub faucet. The faucet was open when I turned the water on and my daughter shut it off as soon as water started coming out. Any ideas about what the problem might be? Thanks in advance.

Sounds like you disturbed some minerals built up in the pipe walls. Since the tub valve was open the crud ended up blocking the inlet ports of the cartridge. Try this.
Shut the water off to the tub valve and open it up. Remove the cartridge and check and clean the inlet ports. Now turn the water back on to flush out the supplies and valve body. Reassemble and test. Better now? Cheers, Tom

I turned the water off at my kitchen sink. Turned it back on by have little to no pressure. All other faucets, shower, toilets and outdoor work.