I don't mind - No me importa I don't matter - No importo

I don't matter was incorrect you should say "It doesn't matter" "I don't mind" means you are not allowing it to happen or quite polite way of expressing you have no preference. "It doesn't matter" means you don't think it can help you, or won't affect the outcome it also can be use to dismiss a suggestion for example, or simply express that which ever option chosen is irrelevant Example: Gigi: "Oh, I took the last pudding cup, I'm sorry." Jose: "That's alright, you can have it, I don't mind Example: Jose: "Should we paint the house purple or violet?" Gigi: "Either one would work; it doesn't matter to me,"

I don't matter (grammatically correct form is actually It doesn't matter.) Means that it does not matter one way or the other

Maybe for examples. If you want to use this sentence "I don't mind", that's mean you not mind to help someone to do anything. you help them with never hope feedback. For this sentence "I don't matter", that's mean you never think someone. you are yourself and they are themselves.