As it is, there are many parts, but only one body. The eye cannot say to the hand, "I don't need you!" And the head cannot say to the feet, "I don't need you!"
This Bible verse is saying, that every part of your body is important.
It is also saying that you are important. You are also part of a body; the body of Christ.
You are just as important as everyone else. God made you for a reason and He put you on this earth for a reason. Don't go around thinking you aren't important, because you are important and mean something.
God loves you SO much and wants you to remember that He will always be there to strengthen you and help you. (Isaiah 41:10)