The Pseudoshell isn't a system of panels or chitinous pieces, but basically an organic over-layer that grows over the suit's armor plates. In exchange for being able to grow over the plates, regardless of shape, they provide no true protection. As a false shell, it's no better than a hard wearing cosmetic layer. Not only that, but they don't grow as a continuous surface over joints, and must be broken up into scales and such, disrupting the pattern further. The camouflage that it can use is basically a very 'natural' pigment based one, similar to what chameleons or cuttlefish use, meaning it has a fair amount of detail, but not to an excessive degree. Its rate of change is also similar to that found on actual animals that use this method of hiding - its best performance comes from when it is holding still, not moving. During movement, it's pretty much just some fancy Digital Camo pattern that happens to always be suited to the environment. Meanwhile, the tactile senses come from the network of nerves that run just under the surface, like skin or most other sensory surfaces. As it is a fake, or false shell, it is not truly rigid either. The amount of flex in this bio-engineered layer is enough that nerves under the surface can be stimulated by physical contact and variations in temperature, resulting in this functioning as a second skin in terms of sensory input.
As for the source of power, it is primarily metabolic, and is supplied by the organic suit that it's a subsystem of. This system regenerates by dividing on a cellular level to rapidly produce stem cells which travel to points that it is neededl The rate of repair is very fast in terms of the capabilities of raw flesh - nearly cancerous - and is enhanceable by the use of the nano/femto flora/fauna that the Ottyo are fond of, "Blue Cordial", which I've linked. Naturally, the regenerative ability of the Medall Pseudoshell is limited by how much material will be given to it by whatever it is part of - if deemed necessary, it can even be allowed to draw organic material from the user for an example.