Sue
Most of the posts here are about what you should do to not let this happen and I agree with them all except the one about oil or even WD40. Not for drilling wood. Asking for more trouble down the road. My opinion.
To get the bit out from what you have now, I suggest you spin the blank and not the bit. It is wood and it should break free without too much effort. Unlike acrylic melting onto a bit which would be harder. If the blank is square it is even easier. You do not say how you did the drilling, on a lathe or a drill press. If it is on the lathe, free the blank from the headstock. Back the tailstock up so you have room and work the blank forward and backward by hand to see if it will free up. If necessary you can use a pair of channel lock pliers. Wrap the blank with some tape or a piece of cloth.
The same method will apply for if in a drill press. Being wood and walnut is very soft so it should break free. Then follow some of the above suggestions when drilling your blanks. Cleaning the drilled hole and bit of debris is a must. That is the most important rule to follow along with keep the bit cool. Also keep the bit sharp. A sharp bit will drill cooler than a dull one. Good luck.