Matdood,
I've just now had a treatment, parts of my hand are itchy afterward and during ( parts that are above or just touching water ). Hands can also go bright red or purple during treatment. I often apply cream to my hands feet anywhere between 10 mins to 30 mins before.
I can only guess it is drying your skin without stopping the hyperhidrosis.
Numerous treatments will probably affect the skin also despite not controlling the sweating.
I also get cold hands and feet and have been diagnosed with Reynauds ( fingers turn white, feet also affected).
I don't know if this is because of hyperhidrosis and treatments but I have always had poor circulation also and now also have a weakened immune system.
If you also have plantar H/H, I would always suggest washing feet and changing socks often. I find if my feet and socks are slightly damp then my feet are always cold.
Afraid I can't offer any real . All the best