I looked at my tags section and saw two numbers without an explanation.
I'm guessing one of these is tag score, and that is what I'm looking for to see my progress towards a tag badge.
Is there an explanation for what the numbers mean?
The number on the left is total tag score (=score on answers + score on questions). This is different from the score on your profile page on the main site, which only shows the total answer score. (See this question and its duplicate for more information about that discrepancy.)
The number on the right is the total number of posts (questions and answers) in that tag.
The number on the left is your score in the tag, the number on the right is the number of posts that you've made that reference that tag.