If you used any amount of neem that close to harvest, I guarantee that's why it tasted bad. I love neem, I use it at least every two weeks up until buds form, but the smell is disgusting. One thing you can do that helps is to rinse off your buds, if you're careful it doesn't hurt anything. Set up two containers of water, one you add one cup of h202 per 5 gal (I think that's right, I have it written down somewhere, double check that though lol) and the other is just plain water. Gently dip your freshly cut buds in the h2o2 first and leave them in for a min or so...if you have some kind of issue, like PM, leave them for a few more minutes, then carefully dip them in the plain water to rinse them off. Hang to dry with plenty of air circulation until the water evaporates. You won't "wash off the terpenes." Terpenes aren't little thingy's that are sitting on your plant like dust that can be "washed off." If I had used neem close to harvest, I would probably add a third bath with some baking soda added to it, which might help get rid of that off flavor. You'll be amazed how much filth comes off of these buds in the bathwater.