First, it is important for you to understand that there are multiple credit scores in the US. FICO is the credit score usually used by lenders to evaluate potential borrowers, but Credit Karma shows you VantageScore 3.0. Both scores use the same 300-850 scale, but differ in the actual formulas used. The exact formulas are proprietary secrets, and we can't know if your FICO score has been impacted as much in the last two months as your VantageScore. However, the credit score companies have revealed the types of things that impact your score.
In the last two months, you have done several things that lower your score:
- Opening the new account required an inquiry on your credit report (hard pull).
- Opening the new account lowered your average age of accounts.
- Adding debt on your new account has increased your utilization.
For the first two items, these will both get better with time, and there isn't really a way to eliminate them faster.
Utilization, however, is an instantaneous number with no history. When you pay off your debt, your utilization will improve immediately, and your score will improve with it.
It is difficult to say how a credit line increase would affect your score. It has the potential to reduce your utilization number, but will also likely add another credit report inquiry.
The best way, in my opinion, to improve your score is to pay off your debt and pay your bills on-time. If you do that, your score will take care of itself, as it had for you before you added "a bunch of debt."
Even at 730, your score is still considered excellent. Trying to raise it by adding accounts and raising your available credit higher than you need doesn't really give you an advantage.