There is no such thing as a stupid question.
You had NO risk from the procedure on your finger. After 4 days a protective membrane had already covered the affected area.
The hydrogen peroxide "bubbled" when you poured it on your finger because most living cells contain the enzyme catalase, which attacks hydrogen peroxide and converts it into water (H2O) and oxygen (O2).
The skin cells where you had the procedure are new, living cells, so it bubbled. End of story.
Please relax, you have nothing to worry about.
RW
Does anybody have an answer?