When my hands first started getting numb, my neuro told me to use cold water- and it worked. During the winter months I keep a pair of insulated gloves to wear because the temperatures can also affect my MS and the hands are always first, for me.
If you have MS, getting too warm can cause problems. For me, my optimal temperature is about 65-72 degrees F. I can tolerate temps down to 52 degrees F before my hands start to hurt and go numb.
As for nerve pain. For me, heating pads have alleviated my nerve pains, but have not done anything for the numbness. My neuro recommended cold compresses, but because they did not help me in my legs, she said that the heating pad, if it helped, to use it. In fact she has passed along my heat pad idea to some of her other MSers who had similar problems. Now, heat pads are not for everyone.
The numbness in my legs went away after several months. The pain relief was more important to me.
Actually I have dealt with problems since 1977, but only knew it was MS since 1982. Still, if you do not allow MS to control you, you can enjoy life and can count your blessings. Yes, there are really bad days, but even then, I have learned to count my blessings.
When you keep your journal, think about what the temperature was inside or outside, how you were dressed, how you felt before and after a bath (a hot shower can zap the energy in many MSers), etc. The main point is that you have triggers which, if you have MS, can cause symptoms to present. If you learn to avoid these triggers, you can control you MS better.
If you do have MS, there will be flare-up's over which you have no control. These can be frustrating, but I have long ago learned to stop and take a break while focusing on other things.
Pity-party invites are very common. You can accept the invitation and find yourself alone with your MS or you can refuse the pity-party invites and move forward. On bad days, take baby steps. Never beat yourself up over your MS. Learn to delegate to others those things you cannot do.
Lastly, back to the heating pad, I think that the heating pad causes the nerves in the area of pain to become over stimulated and then they simply stop responding. MSers have damaged internal thermostats (in a way) due to the nervous system being damaged. I have found that the heating pad alleviates only the pain, but the relief is a RELIEF! If you use a heating pad, you need to move it around to prevent skin damage. For me the pain was intense from my back down to my thigh. I used the heating pad by placing it over the area with the most pain and moving it down to my thigh and then repeating when the pain returned. The pain, when it returned, would start as the area cooled back to normal.