Yes of course you can but I use it as a learning tool, the bud that isnt ready now should have been ready with the rest, otherwise it was sucking energy out of what was ready to harvest.
For example, I just did a harvest with a lot growth that isnt really ready, its a new light, so next time I know cut everything below X height next time I lollypop
The question you should also ask is "is it worth it? " To that I say no its not. What ever you get from this point forward is going to be secondary weed for bubble hash or just fill a jar and sit on a shelf. In the mean time you could have started a 2nd grow.