If it's plastic (which I presume since you mention cutting) be aware it make shrink in the microwave. I've done this with the result being a mess as the liquid honey is forced out while the container shrinks. Using a water bath is safer and be done the cap on. Or I also put it in my oven, still capped, and set it at 170 which is the lowest my oven can be set. I've done that several times. I hate to heat my honey, but some years it crystallizes before being sold and I need to clear it up again.
It doesn't need to be fully liquid when you add it to the boil; just enough to allow you to remove it. It will liquefy quickly in boiling wort. I've also added hot water to the bottle and shaken it up, but you have to stay cautious of the plastic contraction issue if you get it too hot with this method too.