Problem with sanding, tiny dots??

Hello everybody!

I started sculpting my own eyes for my dolls two days ago, and so far I've finished making moulds and have some "casts" ready ^^ It's turning out great, however, since there are always tiny imperfections, I thought nothing a little sanding can't fix. Basically the eyes were a tad bit bumpy or not perfectly spherical, so after sanding, that was fixed, although this is when I noticed micro dots on the resin. They are so tiny, I am not sure if they are holes or dirt, but I tried washing them and they were still there.

The resin I used is Amazing Resin which is white, and the sandpapers were 5 sponge type ones ranging from Medium, Fine, Superfine, Ultra-fine and Microfine. What could be causing this? Was I supposed to wet the sponges first? Is it perhaps the fact that I didn't 'finish' it properly? By that I mean on some of them I just sanded with a higher grit (Fine/Superfine) and didn't use a lower grit (Microfine) after? They didn't look like they needed that though, they were pretty smooth already...

Any tips would help! This is my first time sanding so I do not know what is happening :P
Thanks!

 

Bumping??