(1) After one or two days ...: "After one or two days, they will talk to each other again."
(2) One or two days later...: " I will pay you back the money one or two days later."
注: Sorry. "In a couple of days", "in several days" 与 "several days later" =是指" a few days/several days later..." (再过几天,数天). 翻译不准确.
楼主要的是 !