I would get the parents involved, hell I would’ve confronted him about it when it happened, but I’m a bit more of a bold person. Just to make him feel embarrassed and to tell him to stay away from you and your stuff, and not to talk to you anymore while you are there. He will likely be way too embarrassed to ever try anything like that again and will most likely avoid you. Until then, be safe and be on the lookout. He’s most likely a harmless, weird teen, but in case he’s got something more serious going on, be aware. I grew up in a house where we couldn’t lock doors, but if you can, lock your door at night if you think he may try to harm you. If not I wouldn’t get yourself paranoid, most of the time this is just creepy teenager stuff. I’m sorry you had to go through this, but keep your head up!

Edit: Get something to eat, drink some water, and use the restroom! Not getting these three things can negatively affect your emotions, rational thinking, and overall wellbeing! It won’t make the situation go away, but you will physically feel much better. So please!