I have a bathroom upstair where the shower started with low pressure in the hot water. The stem was change on the cold and hot water now I have no water at all coming out of the shower and sink. Please help.

Thxs

They must have had to shut off the main water supply. I would check the aerator from the sink first... remove, clean, replace, test.

If this fixed sink, remove shower head, clean strainer in neck, test for water pressure without shower head on.. confirm pressure... replace shower head, good to go.. I hope!

It sounds like some sediment got stuck up in the system after shutoffs got shut and reopened. If these ideas did not work... check those shutoffs again... you sure they are open under sink.. Downstairs.. Then get back to us if you have not found the answer. Please RATE THE ANSWER if it helped. Thank you.

Yep, double check the main shut of or stops at these fixtures. Some stops are 1/4 turn but most are 5-8 full rotations.