Flares are very hard to define. Many people get tripped up at that 7 mg dose of Prednisone. I suspect something else happens at 7 mg because pain returning at 7 mg is extremely common and can't be just a coincidence.
My first question would be whether the pain is similar or the same as your symptoms when you were first diagnosed? Typically the pain isn't the same in terms of location, severity, etc.
What I would consider a flare is when the pain is relatively the same. Flares might not be as severe at first but with time the pain gets worse and not better. Flares can usually be distinguished from prednisone withdrawal symptoms because flares get worse. Withdrawal symptoms tend to get better in a few days after a decrease in dose.
Some people would rather not live with any pain so they increase their dose and call it a flare. When I did that, my rheumatologist didn't care but she would rather that I let her know before I increased my dose.
When I didn't know if it is a flare or not ... I let my rheumatologist know via a short, concise and non urgent message. Typically, my rheumatologist would respond in a day or two and want my inflammation markers checked before I increased my dose.
From what I know your body creates 7.5 mg of cortisol through the adrenals. Once you hit 7 mg if your adrenals dont kick in- and they might well not - that’s the trip up. Sluggish adrenals make tapering tough. Maybe try something else to help w pain. I found tramadol w tylenol helpful for the short term.