We had an 8 foot square hottub in our bedroom for 10+ years. Because of the weight, the floor has sagged in that section. The tub is gone now and we had carpeted around it, but now there is a big square spot that has a dip in it. I'd say the dip is at least 1/2 inch. (Our bed is over the spot now) How can we level it out?
The easy way would be to use floor leveling cement. You can built up first with some 1/4 plywood first to get in the ball park.
Without knowing the full extent of damage cause by the hottub I can not suggest a patch job.