1. because you have generalized hyperhydrosis and have undergone sympathectomy, thus do check for underlying health factor like overactive thyroid
gland, low blood sugar
, infectious disease, or any tumor markers.
2. Avoid caffeine, alcohol,spicy food [garlic,ginger], wear loose cotton clothes and socks, instead of soap based cleaners use antiperspirants with emollient
washes, monitor the cause which increases your Sweat, and adapt your lifestyle accordingly. [one factor in your case is depression/anxiety
which make this condition worse]
3. Visit your general practitioner who will refer you to NHS Specilaist.