If the bottom bracket is squeaking because it is binding, it will trash the bearings, and you will need to replace it. Take the chain off and see if it spins freely. If it is too tight, it will bind and not spin freely. If it is too loose, it will have play in it, so tighten it until you get rid of the play, check for binding, and maybe even back off 1/4 turn.
The crank also needs to be tightened properly. Too tight and you will deform the spindle. Too loose and you can do even worse damage. Both conditions could cause a squeaking noise. The consequences of ignoring this could get expensive. Most require about 40 Nxm, not 50. But check the specs of the manufacturer.
Buy or at least borrow a torque wrench. Learn how to perform basic maintenance. Checking the crank and bottom bracket and tightening everything shouldn't take more than 15 or 20 min.