Kristina, I'm pretty sure the teacher only used the forum to make it more interesting for you guys.. And if she added (yet) it means you can correct it and send in new results, which is what I recommend you to do!
Check the theory and similar exercises again, or ask someone to help?
I was one of the better students in class and never thought any worse of someone who didn't know something or didn't solve it right, if they were trying hard.. I often helped others if they asked me too.. See if maybe someone can help?
And maybe she didn't know which smiley to use. Is this better?

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There are at least four+ worse smileys!!
You could talk to the teacher (privately) and say it makes you feel uncomfortable if anyone can see results, can there be a different way of handing stuff in? (Like e-mail or something? Or a password-protected private forum for any individual student that would prefer it?) And maybe anonymous results like with numbers? (Like at Universities?)
If you need to ask teachers anything, maybe go for those you like? Do you have a favorite subject? Can you make some extra effort and be nice to them, then they'll cooperate more easily!!
Believe me, teachers are not paid to bite students heads off!! They just have to look 'mean' because of the disorderly ones!!
Believe me, teachers usually like the quiet students much better than the disorderly ones!!