When should I send a reminder email for recommendation letter?
Given the new understanding of the issue, I'd suggest that you write to him, apologizing for the mail, and with an explicit request to let you know if he will do this. Perhaps your first mail wasn't clear on that point.
But most professors receiving a request would normally assume that the default &quot;yes, I can do that&quot; is understood by the asker and only needs a reply if they won't or can't do it. I'll assume that is the case here if you haven't heard otherwise. But if you need this to be explicit, ask, but say you're sorry for the inconvenience.