Best wishes on an uncomplicated procedure!

Sunscreen has an expiration date and it really does lose effectiveness with time. (seen it on my skin).

SPF only applies to the UVB part of the spectrum.I consider this almost criminally misleading information.
Inexpensive sunscreen works on only UVB.
More expensive stuff (read the label) also screens UVA.

I wear longsleeved shirt, wide-brimmed hat and gloves plus sunscreen on face and neck when out on the prairie in summer.
There was a reason that cowboys wore really wide-brimmed hats.

I reapply good sunscreen frequently at high altitude.

(I like Coppertone Sport)