There are many long terms effects to vaping. One of them is vaping weakens you're immune systems. Also, if you vape you are 4x more likely to start smoking in the future. Vape also contain many chemicals that can cause cancer and more system problems. Nicotine can also permanently damage a teens brain.
There are many short term effects of Vaping. One of them are sometimes, vaping can cause nausea, vomiting, eye irritation, ect. After vaping, you may also experience headaches and dizziness.
There are many harmful ingredients in vape/vapor, one of them is diacetyl. This chemical can lead to serious lung diseases. Another harmful substance is heavy metals such as nickel.
Once you start vaping, it is difficult to stop due to all the nicotine in it. However, a healthier alternative to vaping is for example exercising. It'll keep you busy and way healthier than vaping.
One way to keep away from vape if a friend is trying to get you to use them is to make up an excuse. For example, you could say that you tried it once and you didn't like it. If they still try to offer it to you after refusing then they aren't a good friend.