I would say it more like: "May I please borrow $100? I will pay you back in two months." (or: "I will repay you in two months")

Foreigners often confuse verbs "borrow" and "lend". To borrow is when you take something with the intention of returning it and to lend is when you let someone take something that they will return to you. I need to borrow $500 to fix the car. Do you think the bank will lend it to me? I'm not sure, I don't think they make loans under $1,000. Could you lend me some money? I can pay you back in a month How much do you need? I need a hundred dollars. Sure, I can do that. Excuse me, Raj, may I borrow $100? I'll pay you back in two months. Oh, I'm sorry, Sumesh, I just don't have it to lend. I'm short on cash until I get my salary on the first. May I borrow $100? You've lent it to me before and you know I'm good for it. I get paid in two weeks. Errrm, OK! But you gotta repay me on time so I can make my rent next month.

As Logan said, be careful of borrow and lend. If you borrow, you take. If you lend, you give. You probably meant to say, "Can I borrow 100 dollars? I will pay you back in two months," or "Can you lend me 100 dollars? I will pay you back in 2 months." If you say "Can you borrow 100 dollars for me?" you mean that your friend should find someone else to borrow $100 from, then give it to you.