Aye, good enough, it all fits together nicely even if the punchline, although funny, isn't too 'punchy'. In my opinion you could decide whether to use 'Now I don't have to tell her she's a bad kisser' OR 'What was her sister's number again' as the punchline, and it may even benefit from taking the first sentence out completely. If it were my comic, i'd have left the last panel with the girl saying simply nothing, giving the guy a perplexed and accusatory stare (or at least thats how it'd look to me), and the guy thinking 'Now, what was her sister's number again?'. That's me and my style though, and many will think the comic works better as it is now. This is because its good anyway.
But yes, make more, please.