Does she have a stomach pain on urinating I was wondering if she may have a UTI and feels she wants to 'go 'all the time ..?
Also, if she's holding in her urine a little might be leaking into her panties. Make sure they get changed a couple times a day and maybe the smell will go away.
Have you asked her doctor about this? If it's just behavioral I would go back to the old techniques you used to potty train her. Remind her to use the bathroom every hour, set an alarm if you need to. Reward her when she does use it, but don't ever punish her for having an accident unless she does it on purpose. Is she stressed out about something? Sometimes regression is a coping mechanism people use to deal with something stressful.
Hmmm. Are there two things going on here - she smells like pee, and additionally she is also peeing in her room, or does she smell like pee because she's always peeing in her clothes?
If she smells like pee when she's dry, it's most likely she's getting too much protein and not enough carbs in her diet.