He hasn't filed a chargeback by the sounds of it, but threatens to if PayPal don't give him his money.
A chargeback is when someone phones up their bank and tells them to reverse the transaction placed on a credit card.
Chances are he is bluffing, a lot of people threaten to call their bank but nothing ever comes of it. If he paid with PayPal balance as opposed to a CC then it's up to PayPal completely and nothing to do with his bank.
You're in -$98 because PayPal temporarily deduct the funds of any disputes in action, the easiest way would be to solve the dispute and see what the outcome is.
If it's a physical product delivered, and you have no tracking notes, then that's your fault and get focusing on making some money, or ditch the account and leave. No one is going to come after you for a measly $98.
Worst case scenario, your IP is tracked so if you try and make another PayPal account, you'll get a message sometime saying "HEY! You owe us 98 bucks!". I've seen that happen before.
This guy obviously started a dispute on PayPal, what "reason" did he choose. Did he leave any extra notes? Leave them all down here or send me a PM and I'll help you out if you like.
Also, CHILL OUT! You're too young to get into any trouble, it's PayPals fault for not verifying your identity in the first place.