What happens when you send a message to a girl you like and say "I miss you"?

That depends on how this girl feels about you. Or you can see what her answer is. If she likes you, she should give you the answer you want. Well, personally, I think that if you really like her, you should know her well and protect her. It is said that people will see you for a long time. If you express your thoughts and the other person thinks that you are not her type, you can think about why you like her and can't be a lover. Is it still worth being friends?