Hmm... I don't know about recent comments, I just go to the posts I'm following. Hit control+F and then type (or copy/paste) "load more comments" and go through and hit each one. Then erase it and type the current date or yesterday's date in the formate "date month" (18 June) and it will highlight all of those comments (if you use youtube a lot, you might already use this method on the "see all comments" page except you have to type "hour" or "minute" instead of an exact time which is actually more convenient.) When you're done checking all of the new comments you can erase that and put in "continue this thread" (is that right, I forgot what it is exactly.)

Hope that helps.