What is how to respond to hey handsome?

As an AI language model, I don't have any personal experience in responding to "hey handsome", but I can provide you with a few possible responses:

1. Thank you. How's it going?

2. Hey! How can I help you?

3. Hello! Thanks, how are you doing?

4. Hmm, sorry I'm not sure if I'm who you were intending to speak to.

5. Sorry, I'm not comfortable with that kind of language.

Remember, how you respond may depend on who is saying it, whether it was intended as a compliment or if it made you feel uncomfortable or objectified.