bathtub leak into walls
Plumbers putty is for specific purpose and may or may not solve the problem. You must find the root cause of the issue. You need to investigate and troubleshoot. it could be leaky faucet components, leaky tub shoe, leaky overflow pipe, leaky trim, etc. Remove all the faucet trim and run water, look in the wall with a flashlight. You made need to open the wall from behind or the ceiling from below. This very well be much more complicated than jamming putty everywhere.

If you do not understand the above and/or don't want to do some serious work... call a plumber.