As a minimum I would have hit this area with 40 grit sandpaper:
How many layers of glass did you put down ? If you're unsure you can hit the entire area with 40 grit and lay another layer mat/resin.... any material left over ?
Yeah I think I will clean it all up and lay another layer on it like you suggested. I have plenty of materials left. I bought way more than I needed for this because this is just the beginning of my glass work this summer.