Lou - I can't imagine that the numbness is related to MMS. This is not a "normal" herx reaction (which is nausea, vomiting, extreme tiredness - all caused by the body's inability to get rid of the toxins as fast as they are being killed off by the MMS) - Yes, do go slowly - and you can also do "washes" on her back where the tumor is.
Amanda Mary has given us excellent directions - I will paraphrase them:
Make your MMS (You can use use the skin formula, if you wish - 10 drops activated, wait 30 seconds, add an ounce of water) - (once this is together, then if you want to add DMSO, you can do so at this point, I'd start with 5 drops of the 70%, allow the DMSO a couple of minutes to bond,) then putting this mixture in the palms of your clean hands, gently apply to the back. Don't rub it in. Watch, and if your mom says her back is itching or burning, then wash it off. It will have done what it needs to do by that time.
Alternatively, you can spray MMS skin spray on the back and then apply the DMSO.
Some people are sensitive to DMSO and it may cause a burning sensation - usually what we do at that point is dilute it a bit further. Morton Walker, in his book, DMSO, Nature's Healer, says to use DMSO at the most at 70%, or even 50% above the waist.
Be sure to mix your MMS with distilled water (if you're using CDS, you will have made it with distilled water)- If you want to use CDS on the back, you can use 4mL of the 3000ppm CDS for each ounce of water.
Another option for your mom with lung cancer will be inhaling the fumes - Jim Humble is very explicit in his book on how to do that - you must be VERY careful and not inhale too much. Do you have the book?
Amanda Mary, please feel free to correct my description of your protocol. Thanks!