| There is no known medical cause of ganglion cysts, so I think you can rule out punishing yourself for cracking your knuckles. The good news is that if you have been properly diagnosed with a ganglion cyst you are not in danger of it being cancer. The bad news is that it will eventually cause the muscles to weaken, so you usually have to have it removed.
Sounds like I have experience -- yep -- don't worry, you will be fine after a couple of days. Something that helps is to remember to keep your hand above your heart (for 24-48 hours) to keep swelling down. A pillow to set your elbow on while studying or doing other things makes this easier.
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