Excess sweating from my head (vertex part). What can I do to reduce it?

Thankfully, sweating does not cause baldness.  Craniofacial hyperhidrosis typically involves several treatment options:
Botox- The standard for hyperhidrosis with local side effects only.  May require a larger dose for the scalp.
Oral medications- Typically involve anticholinergic medications such as glycopyrrolate and are not well tolerated.
Topical medications- Usually not advisable to put drysol on the scalp
Surgery- May be last resort for some patients but hyperhidrosis treatments tend to be moving away from this
LASERS/Miradry/ Radiofrequency- Very effective in other parts of the body.  Not ideal for scalp as some hair loss can be seen.

Botox injections are safe to use in the scalp area, and should provide relief for 3-6 months. There is no association between sweating in this area and hairloss....Best luck, Dr P.

Thank you for sharing your question and I am sorry to hear of your sweating difficulties.  Though I do not think your sweating is contributing to baldness you can treat it with administration of Botox to your scalp.  This should give you 4-6 months worth of relief.  Hope this helps.

Treatment with Dysport or Botox can reduce sweating in many areas of the body. Sweating is not associated with hair loss. Best, Dr. ALDO

It is unlikely that sweating would cause baldness. I suggest you see an expert there is a lot of non invasive options (Botox, Glycopyrrolate, Beta Blocker) for this to give improvement. For hair loss, there are great non-invasive options like PRP/progesterone which can be used in combination with Rogaine for great results. See an expert. Best, Dr. Emer.