You either cut into the wall or wait. If you can, I would isolate those pipes by turning valves off. The pipes may have froze and split. You won’t know until they thaw, then you might have a flood. Do you have access to the plumbing lines in your basement? You could install a few valves in the lines and close the new valves so you at least isolate the problem area.
One of the downsides is that you may be without water in other parts or your house / bathroom, depending on how the plumbing lines are installed.
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