Why don't I gain reputation when my edit is accepted?
I edited in here but I didn't gain any reputation.
Given your low reputation (suggesting that maybe you don't know your way around the site much), and some other things which factored in, I took the liberty of looking at your reputation history and contributions.
Of 7 submitted 'suggested edits' at the time of this post, you had six of them rejected, but only a single one ever accepted - this one which was only 'accepted' because the original poster of the post accepted your edit as valid.
And for the single suggested edit you had accepted, you did get reputation for it (this is from your reputation tab and is not private knowledge):
All other 6 submitted edit suggestions were rejected by the community, and you don't get rep for those being rejected.
You only gain reputation from an edit if the edit is accepted by either the original poster or by community review consensus. You get absolutely zero for rejected edits.
Here's links to all your specific edits, so you can see why they were all rejected. Had it not been for the OP of the one post, though, you would have 7 rejected edit suggestions instead of 6. Just keep that in mind...
Unless you are the owner of the post which had the edit suggested to it, or you are a diamond moderator such as myself, an "Approve" vote on an edit is worth absolutely nothing unless you get a second "Approve" vote on it. It requires two "Approve" votes to accept a suggested edit unless you are the owner of the edit-suggested post or a moderator and hit "Approve".
Similarly, it also requires two "Reject" votes to reject a suggested edit, unless you are the original poster of the content that had the edit suggested to it, or a diamond moderator. (And this is why I don't go through the suggested edit queues much anymore - my moderator diamond gives me binding votes which means whatever I vote is whatever happens to that suggested edit - and in most cases it's 'reject' for reasons similar to why yours were rejected by the community at-large.)
A bit of advice, if I may, also. Given the edit suggestions you made, and the fact that they were all rejected for the same reason, you should really revisit what you're doing in edits. Because all of your suggested edits fit into the category of "doesn't help readability, or are completely superfluous and unnecessary", or "Actively harm readability", or fit into the category of "You should really propose this as a suggestion to the OP by comments and not by adding information to the post via editing".
You should review some of the actually good edits done throughout the site, and observe why they are good or not. Or, ask for guidance on how to edit better (though we'll probably hand you examples of good edits, bad edits, questionable edits, etc. and tell you to review them and burn the differences into your mind before editing things yourself, again.)