How do you know if a dent is bad?
I'm asking this question because today I found a long dent on the top, between the fingerboard and the bridge. It's not deep or anything, just long and flat. It's undetectable so I couldn't take proper pictures but when I tilt it to a certain angle I can see the light reflecting off of the varnish and showing the dent. Actually, I'm not even sure if it could be called a dent. It's just so flat. I can feel it when I run my finger there. It's on the right side, just before the f hole (not the left size where there's the sound post). It didn't affect the sound. But does it need to be fixed?
I saw some people saying that it doesn't affect the sound so it's okay to keep it.
Should I adjust the bridge or something? Can something like this get worse?
Get that violin to the Luthier STAT! You have a cracked top plate. Chances are it can be repaired but ignoring it will only make things worse.
Violin tops can deform without cracking, which sounds like what you are describing.
Update: I decided to listen to your advice and loosen the strings the way you said I should but I also put a homemade humidifier (a slightly damp sponge in plastic zip lock bag with slits) inside the case and after an hour when I checked my violin again I noticed that the dent got smaller. It was slightly stretched out towards the tailpiece but now it's within the bridge and fingerboard.
You had three replies. Each can be summarized with the words 'take it to a luthier immeidately.' I foresee a long chain of replies each saying the same thing, until you are persuaded, so to provide a bit of variety, I will give a dissenting view: if it is a cheap violin (the kind dealers buy for $150 and sell for $1500) it may not be worth getting it looked at professionally because you can replace it as and when required.
@john birchall you're right. It is a cheap student violin. I bought it for 200$ and it came with a case, bow and rosin. So i guess it's okay to keep it like this and replace it when I need a new one?
What you have is probably crack starting even though it does not look like a fully fledged crack. It will certainly cost over $200 to fix. Buying new instruments is fun, and you will want something better soon (unless you were very lucky with this particular one).
Honestly, i don't think my parents will take this dent seriously enough to get it repaired anyway.