I'm still fairly new to the hedgehog thing... just got Harley last week but for the first few days we had him, and still even now, he doesn't drink much. I didn't actually see him drinking at all for the first 4 days or so. I did give him the option of using a bottle or a dish though, he seems to use both. Maybe try putting a bottle in as well? It's easier to tell if they've been drinking with a bottle too. just make a little mark where the top of the water comes to when it's on the cage and see if it's gone down in the morning 