In that context, "a few days" sounds much more natural.

General rule (there are exceptions): Use "few" when you want to talk about the quantity of days. "We spent a few days in Cancun." Use "some" when you want to talk about frequency or with uncountable nouns. "I don't want to get out of bed some days." It's more common to use "some" with "time" (because "time" is an uncountable noun). "It's a good place to spend some time."

thank you!