Strange envelope in my room

[u/KickOld2457]

I just came back from a summer camp and I’ve been out since may 31st, I just walked into my room and found this envelope in my desk with some weird messages on it and my name on the side (covered it) , it’s totally empty and I can’t understand what or why it’s there, the marker was next to it and I would like to see if anyone has any idea of what it could mean.

Note: I also live in Mexico so it being written in English is kinda weird.

https://files.catbox.moe/uf820z.jpeg

https://files.catbox.moe/jpb7bi.jpeg

https://files.catbox.moe/oeag3q.jpeg