If oxycodone is reduced to a pure powder form would it cause numbing of the gums?

I tested an unknown white powder that I found after my husband's death and it numbed my gums and tested blue when using a police type test kit but his autoposy did not test positive for cocaine but for oxycodone. Is it possible that oxycodone would result in this result?If oxycodone is reduced to a pure powder form would it cause numbing of the gums?
yes it would, it is a narcotic and if put directly on the gum it can cause numbness, tingling or even burning/stinging. I am sorry about your husband GOD BLESS~~~