I've had my second laser hair removal treatment on the chest. What are these black spots? (Photo)

Hi T99.  It looks like you have had an excellent treatment.  The little black dots are the ends of the charred hair.  They become more visible after the hair starts to fall out subsequent to the treatment.  There is no cause for concern with the picture you posted and it looks like you should achieve excellent results with that kind of treatment.  For examples of Long Beach, CA laser hair removal before and after pictures, click the link below.

These appear to be the ends of the hair that is charred.  These are of no concern.  They can be shaved off.  They appeared because they might have been below the level of the skin before and are now being pushed up from the follicle as the hair is extruding.