This is not a place for telemedicine or making medical suggestions only for educational purposes only!
Food grade Hydrogen Peroxide degenerates, decays, or transmutes rather quickly because it is pure, free of other chemical stabilizers. So it probably was sitting on the shelf too long and turned into water. The drug store stuff is stabilized.
Oral doses some say to start with one drop and that may be too much. I have heard the Hertz reactions are very common as there is a die-off of bad "bugs". So may need to put one drop in a glass of water and start with a quarter or half glass. I think the Hertz rxn can be minimized with Vitamin C and NAC and perhaps clay while drinking the peroxide.
For a bath the OTC drugs store stuff is ok if you are not too hypersensitive or mentally not too rigid. A pint of 3 % is enough although a quart is fine if you are shopping at Costco. Some suggest a cup or two of the food-grade diluted in a full bath.
Don't deliberately put Food Grade or anything not diluted on your skin to test. Maks sure while working with 35% that you are wearing lavatory safety equipment including goggles, gloves, closed-toe shoes, and protective lab coat as a minimum. If skin or eye contact flush immediately with running cold water. Read all safety instructions and follow exactly!