Thanks for your query.
I understand your concern.
Relax,there is nothing to worry.
Sweating over forehead and around palms is commonly seen in young children.there is nothing to worry and it settles of its own.
Regarding premature greying it is
I suggest you to give her good nutritious diet rich in proteins
,vitamins and minerals
Give green leafy vegetables,salads,fruits,almonds,cereals,milk and milk products and plenty of fluids.
Hope I have answered your query.
Let me know if I can help further.
Wishing your baby good health.