Here's some information from perplexity.ai:

For polymyalgia rheumatica (PMR), standard pain relievers like Tylenol (acetaminophen) are generally not effective for controlling the underlying inflammation and symptoms of the disease. The mainstay and most effective treatment for PMR is a low-dose corticosteroid, typically prednisone, which rapidly relieves pain and stiffness by reducing inflammation.
Tylenol may be recommended to help with pain during the process of tapering down the steroid dose, but it does not address the inflammatory cause of PMR and is not considered a primary treatment. Similarly, nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen have limited effectiveness; while rare cases have shown some benefit, especially when started early, they are not standard therapy and are generally much less effective than corticosteroids for PMR.
In summary:
Prednisone (or another corticosteroid) is necessary to control PMR in almost all cases.
Tylenol may help with pain but does not control the disease itself.
Do not rely on Tylenol alone for PMR; consult your doctor for appropriate corticosteroid therapy.

If PMR is left untreated, ongoing inflammation can significantly impact quality of life, increase the risk of vascular complications, and, in rare cases, cause permanent muscle or joint problems. However, with appropriate treatment, most people recover without lasting effects.

General Health Impact: Chronic inflammation can cause fatigue, weight loss, low-grade fever, anemia, and a general sense of feeling unwell. Mental health may also be affected, with increased risk of depression and emotional distress.