What does it means when some skin from your rectum goes out a litle from your ?what can you do to cure it?

Hi Im 16 years old and i been having constipation ever since i was 10. Last week i went to the bathroom to do my thing so it was very painful, after that everytime i go back to the bathroom and push some litle skin from my rectum goes out a litle. And im worried about it. What does it means? what can i do abou it? THANK YOU