Oh no...
IIRC, the (30-50%?) risk of pulmonary embolism (
PE) from
DVT is greatest in the first few days/weeks (because clots are still loose and can break up and fragments get swept 'upstream') so speed of diagnosis and treatment is of the essence. A PE is
extremely serious. Any delay in treatment could have dire consequences.
I can understand why your wife didn't want to spend any more time waiting at the hospital, but I would go back there ASAP and if necessary camp out until they test her for clotting. A simple D-Dimer blood test detects 19/20 of clots and (certainly in normal non-Covid times) results can be back in an hour or two. If there were a positive result (or maybe even with a negative result if the doctor is concerned about the lump) she would probably then have an ultrasound scan of the vein, and maybe even a CT scan. Ordinary X-rays won't really pick up any clot.
Good luck!