Answer: (Informal)
Hey, buddy! How are you doing? I know you're going to get better! Ok, guess what happened today in school...
Somebody put a note on the back of (Mean person, insert name) and (mean person) freaked out! It was really funny though. The note said "..."
Also, good job! My friend, the one who gets to hand out graded papers said you got a 99% on your history test! Congrats, dude!
The class pet lizard escaped the classroom! When the teacher found it, it was on her leg! Oh gosh, she started screaming like a little kid! I wish you were here today, you would of cried with laughter!
I really hope you can come back to school before the christmas. I have an amazing present to give you! I think you'll like it!
See ya soon, (get better soon),
from (you)