Is it safe to take birth control pills for only few days to change you're cycle? I have done it before in the last 3 years only twice and it worked, is it safe though

Your doctor will prescribe them to you for that reason?

I will note, I have moved your question, you asked it in the "forum" section where you ask questions on how to use this forum.
Please take time and look over the stie and always find the proper area to ask your question in.