What version of the Taz do you have? Specifically is it a Taz 3 or before? The Bed mounts on the Taz 3 would allow lifting of the Y axis frame. I would check that first. if it isn’t that, something is out of allignment but good and you are going to have to do a basic level reset to get back in the ballpark.
Depending on which printer you have, this process will be a little different, but I’m going to assume you have a Taz 4 or 5.
Step 1. With the nozzle up away from the bed a few mm, use your verneir calipers to measure between the top of the bottom leadscrew bearing, to the bottom of the leadscrew nut on both sides of the printer. That distance should be identical. if it isn’t identical, power off the printer, disconnect the motor to prevent electrical pulse into the controller board, then manually turn one leadscrew until both sides are identical. Then reconnect and power the printer back on. You may also want to measure from the top of that same bearing, down to the lowest part of the frame and make sure both sides are identical. They should be from the factory, but I have heard of at least one that slipped.
Step 2. With your X carriage level to the Z motor mounts, check your bed against the nozzle by using a feeler gauge. If one corner is still significantly off, you will also need to reset the screws. Find which screw is down in the bed mount furthest, and then back it off until the bottom of the screw is just flush with the underside of the bed mount plate. Now turn it in 15 more turns. Use this as your starting height, and adjust the bed level height to that point. Now move the nozzle to each of the 4 corners, and adjust those screws to match.
Step 3. Run the bedcalibration gcode file that came on your SD card multiple times, making minor adjustments as needed, until you get a good contact pattern all around, the lines all look parallel and symmetrical, and things are just squished down enough.
If you do all that and its still off, it’s possible you bent something important.