Weird marks/zits/pimples on the bottom my surfboard

Hi,
I got a new board, completely unused. I was waxing it and noticed these white marks on the bottom of the board (see the image).
Any ideas on what's causing them and what the best action is?
Thanks
I got a new board, completely unused. I was waxing it and noticed these white marks on the bottom of the board (see the image).
Any ideas on what's causing them and what the best action is?
Thanks