Mother toke tylenol for pain. she took 6-8 a day 3 hours apart for 3 weeks. she stopped taking any pills for 3 weeks now. but her condition is getting worse. everything she eats taste bitter. hasn't ate in 2 days. signs of irreversible liver damage?

I doubt liver damage from taking tylenol unless she combined it with drinking alcohol. I recommend consulting a specialist in internal medicine for a thorough evaluation including thorough history&system review, complete physical examination & appropriate testing. She may be referred to another specialist such as a gastroenterologist depending upon the assessment.