Your weight is the same whether you are IGE or OGE. So, the total reaction vertical component, balancing weight, is the same.
What changes is the angle that the induced flow comes in - OGE it is pretty much vertical, but IGE it is restricted by the proximity of the ground, and its angle changes.
The end result is that in OGE, the total reaction has tilted back a bit, making the Induced Drag bigger and requiring more Power (collective pitch, leading to more N1 and fuel) to hold the same weight up there.
The only difference between IGE and OGE is the Induced Drag and the power required to overcome it. As Nick has said, there is no pressure bubble, it is simply a convenient way to describe the effects.