What size are SMP dots? I'm scared they will look fake

If done properly the SMP should nicely conceal your donor area. The dots of pigment should be about the size of a ballpoint pen mark, and depending on the pigment used will gradually fade after 8-10 years.

I am not an SMP specialist, but I refer to Sabine / Prohairclinic since I have seen a lot of her work.At a normal distance, SMP is not noticeable for a layman.
However, your FUE dr. has not done a proper job if he depleted your donor area to the point where SMP is required to disguise the problem.

The dot size is controlled by the operator and their skills.  The new laser tattoo device has even more precise control over it if the operator is not as skilled and doesn't have the years of experience