You are an able physician, allowing you to mend wounds quickly and get your allies back in the fight. You gain the following benefits:
By spending a few moments examining a chemical — a vial of liquid, a packet of ground powder, or the like — you can determine whether the substance is intended to harm or heal (or neither). This examination does not reveal any specific information about the substance (such as that a powder is actually an inhaled poison, or that it paralyzes its victim), only that it is either harmful or helpful to those that it is used on.
Due to your vow, you are expected to cure the ill, regardless of morals or prejudice, even if they are your enemy. It is considered a horrid evil to intentionally kill a doctor for no reason. As such, intelligent enemies are less likely to target you, (Provided they are not frighteningly evil in a manner that would be inappropriate for younger audiences) and even your enemy patients will at least not attack immediately while under your care. What happens after they leave your care...? Well you can't decide their fate. Restored individuals may be grateful, or feel some form of life-debt to you. Enemies may repay you by specifically choosing not to kill you, or they may give free information, or a scout you once saved may turn a blind eye to your presence.
Provided you stay true to your vow, (as best as you can) you can make use of any hospital or medical facility, (typically located in churches, noble estates, universities, and other places of higher learning) as temporary residence for yourself, your patient(s), and your companions if there is room for them.
However, if ever you are proven to have broken your vow, you will be fully and publicly discredited as a doctor, and other doctors who pay attention to medical society will recognize you as such.