"How can I avoid future awkwardness if he doesn't like me back?"

I think you have a good idea saying that you liked him at some point recently, that way it's not as direct as saying I like you. This way if for some reason he doesn't like you back you can pull the "I said i did like you, I don't like you as more than a friend now though" card, and just laugh it off. If you laugh it off and don't make it awkward , it won't be awkward.

However this could trigger him to admit he liked/likes you too which is always nice.

Just try not to be too hard on yourself and laugh it off, and if it works out, great!

Good Luck!