I have mostly gray hair and get it highlighted blonde w/most hair appearing blonde w/some dark underlying hair. I have gray roots growing out over an inch and want to know what OTC product I can safely use to match color and not damage naturally curly hair that's been bleached/highlighted?

What OTC product I can safely use to match color and not damage naturally curly hair that's been bleached/highlighted?

You need bleach to get it light enough and since you highlight, that requires a professional to properly place the higlights. If you were to bleach all of the roots, you would have big problems. Blonde tints will make it super yellow and will also give you problems. Basically, what I'm saying is that there's no simple OTC product to help keep your roots looking good. Why not plan a salon visit along with your travel plans?