Start with the fact that nothing in this space is risk-free and that the useful question is which risks are reducible at what cost.
Material risk is reduced by independent testing: identity, purity and quantified content on your own lot, before committing to a larger order. That is the only step that addresses what is actually in the vial.
Keep a written log: date, dose, lot, site, and anything noticed. It converts an anecdote into a record and is what makes any later consultation productive.
Slower titration than the licensed schedule reduces gastrointestinal adverse events, which is the mechanism the licensed schedules themselves rely on.
The safest option in every case is not to use unapproved material at all, and that should be said rather than implied.
Tell a clinician. It is the decision that makes every other problem solvable.