Sorry to be a bummer but Byron is easily one of the worst places in the known universe.
Depends what you like to skate..
As Matty said, Yamba is nice and recently was upgraded (the skatepark that is).
Ballina has an indoor skatepark thing at the skateshop in the industrial estate that has a concrete loop and some other diy elements to it.
Everybody loves Mullum - I don't know, it's just a lot of transition though - also has a diy zone off to the side.
Nimbin is kind of a dumb skatepark, the mini-mini ramp is fun.
Numerous private vert ramps/mini ramps/bowls and more if you tap in to the right folks and you're not a horrible person.
If street is more your thing there's not a lot of actual street skating to do - yamba has spots around town, lismore has spots, goonellabah is the most street skatepark until new lismore gets built - to be honest though you probably don't want to spend any of your holiday time in goonellabah. I guess suffolk park (which is basically byron) also has a little streety zone with diy ledges and rails on the basketball court next to the skatepark. Kind of wollongbar too, it's pretty mellow though.
Number 1 tip would be not to think Byron is the destination - checkout everywhere else in the area. Sorry, maybe you'll love it. It's pretty rank though as far I'm concerned - especially if you're trying to get out of sydney, might as well just go to bondi.