I'm not sure I understand the question. I think that the CategoryID column already has a comma separated list of IDs, that is what I got from your post.
If you want to just show the category names comma separated you can use:
$query_CategoryName = "SELECT GROUP_CONCAT(Name) AS AllCats FROM LockoutPoints WHERE ID IN (".$row_Products[‘CategoryID’].")";
And then you can just show the column AllCats and don't need a repeat region.