I take selfie everyday but i forget to take one today! What should I do with my mistake?!!?

You could just take two selfies for the next day or something, No reason to panic over it.

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1. Throw all the others out and start over.
2. Ignore the fact you are missing one.
3. Take two, changing clothes (if wearing any) between them, and lie.

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Go back to school and learn how to write a sentence.

"I take selfie everyday" should be replaced with "I take a selfie everyday"
"but I forget to take one today!" should be replaced with "but I forgot to take one today"
"What should I do with my mistake?!!?" should be replaced with "What should I do about my mistake?"

If you speak English you should learn to write it. <