The Telepath 9th tier power: Psychic Chirurgery - You repair psychic damage or impart knowledge of new powers.
Psions have a limited number of powers along the lines of Bards and Sorcerers - limited powers, but can use them as much as they want. Psions are even more powerful with the use of Power Points that can be allocated in any fashion towards any ends within their chosen Powers.
IF Psychic Chirurgery is available in Pathfinder, there may be restrictions on its use or availability. It may also be altered from the SRD version. Please check all available sources - campaign and otherwise.
If the SRD version stands, you either need to be a Telepath or have a Telepath use it for/on you. Once two Psions have the power, they can effectively "trade" powers.
Besides Telepath Psions, Vitalists also get Psychic Chirurgery on their class lists. As a last resort, if unable to find a Vitalist, Telepath, or character who gained Psychic Chirurgery through a use of Psychic Chirurgery (perhaps you want a power only available to classes that don't get lvl9s at all), you can always buy a power stone, and combine it with whatever buffs (perhaps from further consumables purchases) are necessary to allow whomever you do find with the desired power to use the stone successfully. Expensive, but it can be done.