I assume that when you say, Muslima, that this is a spelling error and you do not mean an army of Muslim women.
A lost Muslim army, will certainly be reintegrated into the Abbasid Caliphate, which will re-establish contact and demand reunification, which will be granted, assuming the Abbasid are still strong in 800 CE. The Abbasid caliphate was already the dominant power in Sogdia, Kwarezm and so forth, a lost Muslim army that manages to conquer a sector of the former Celestial Turk realm, will be hailed as great mujahadeen by the Abbasid realm and be given autonomy and rulership to conquer what it pleases. This will be difficult most certainly though, entropy will be on the side of the steppe hordes as the Abbasid Caliphate weakens in its authority.
Remember, in this early period, the Abbasid state did not accept any state or land as Muslim unless it was at least nominally under Abbasid Caliphal protection and rule.