https://www.amazon.com/B12-Methylcobalamin-Spray-SKU-90810/dp/B07DH8QB6Z/

Serving Size: 3 sprays (0.5ml)

Active Ingredients: B12 (as Methycobalamin) (600mcg per serving)

So 1 spray is 200mcg, a reasonable dose.

Also see this: https://www.reddit.com/r/PlantBasedDiet/comments/b4e3fu/b12_supplement_dosages_are_ridiculous_i_cant_find/ej6gt73/

Some studies suggest a possible association between high-dose, parenterally administered B12 (0.5 to 5 mg) and acne formation. However, the acne lesions were primarily associated with hydroxocobalamin rather than cyanocobalamin, the form used in the United States and Canada. Furthermore, iodine particles in commercial B12 preparations may have been responsible for the acne. In conclusion, the evidence from these data was considered not sufficient for deriving a Tolerable Upper Intake Level (UL).

So it would seem cyano is less bad than hydroxo when taken at huge dosage.

I'm a bit hesitant to start taking a B-complex because I'm so sensitive to supplements and medications in general (lol, obviously)

This is a good idea. Try to avoid the multi. They're crap.