Hello all! My dad recently got a new case for me. With the side panal on my hard drive gets extremely hot, usually 58c

Now I just took the side panal off and it is staying on 42c! So i'm guessing the case I got is rubbish? Is it safe to keep the side panal off?
Dust is not a huge problem because the case is not touching the carpet (it's on wood) and is in a slot inside my desk.
Thank you