Will I need larger and larger does of lyrica (pregabalin) over time?

Not necessary. I do not find the need to keep upping Lyrica (pregabalin) in my patients provided they were titrated to an effective dose initially. Certainly if you start very low and stay there then move up slowly you will keep going up and up.
Depends with limit. There is a max dose and can not go beyond that. Higher doses have more side effects. Studies do not support the 600 mg per day dose as being superior to 450 or 300 and of course it will have more side effects. Check with your doctor and see if you need higher doses than whatever you're getting now or do something else.