There is a previous discussion on this same topic here (we recommend searching our site before asking). As the previous discussion is somewhat incomplete, however, I'll offer a little more.
First, acupuncture doesn't treat conditions per se, so when you ask questions it is helpful if you can provide more details about the patient, what your overall diagnosis from a TCM perspective is (or whatever perspective you are using), and what points you have tried and why you feel they are not working. This allows us to offer more details.
Morton's neuroma is an enlarged nerve, usually between the 3rd and 4th toes, that leads to varying levels of pain (can be severe) in the ball of the foot. As the symptoms can be similar with bone spurs, plantar fascitis, and other nerve problems, a diagnosis from an MD or Podiatrist can be helpful for targeting the local aspect of the treatment.
Treatment involves constitutional treatment based on their overall signs and symptoms (i.e. yin deficiency, dampness, etc.), and a mix of local treatment points. Locally I most often use Bafeng, GB 39, UB 60, UB 57, KD 1 if tolerated (or SP 4 if not), KD 3 and ashi points. My idea (with most foot problems) is to loosen the calf and the achilles area to reduce tension on the bottom of the foot and improve circulation - tuina is also good in the calf and achilles area.
Footwear is also something that needs to be addressed. They should -never- wear flip flops and avoid high heels and will most often benefit from shoes with a wider and stiffer foot bed (birkenstocks are ideal for this).