Going back to the original question, that is clearly an opportunity for an interesting myth. Godtime being what it is, the first question is what Arroin is involved, the powerful healer or the broken non-magical medic. Considering troll chauvinism and availability of healing, it would be better for it to be the second case, and probably involve a magic dead area (at least one is not that far from Dagori Inkarth). That may well be a way for an Arroin devotee to become a troll-friend, at least with trolls in Dagori Inkarth, or a way for a troll to extract some healing from human healers, possibly for iron wounds.
As an outline from the troll side, KL sons foraging for food for their mother stumble on a depression where nothing lives. Desperate to find food they scout the whole area. Finally they find a chaos beast shaped as a bull or heifer Praxian beast (depending how much you wish to antagonize Storm bulls, in case you place the myth in The Dead Place, but they find their magic fails, and without their magic they cannot defeat it. When all seems lost KL arrives with her entourage looking for her missing children. She devours the beast whole, but it has spikes of death metal that wound the All-mother insides. No healing (XU may be involved if desired) seems to work in this place, and the death metal wounds do not heal naturally. Looking all over the place favoured son X (your choice who is the favored son, either an ancestor or Karrg) finds hiding in the dead area a weakling dressed in white, and remembering that is the color of healers among the weak, brings him / her back. The healer shows no fear, despite its weakness, and after discussing the situation, agrees to be swallowed by KL. Although she still suffers from heartburn, the unguents and salves of the healer take out the poison of the death metal out, and the great mother can heal again. As thanks, she spits the healer out, in case she or her children need the healer again.
Just an example of how a throwaway sentence may become an interesting event, or a HQ opportunity. The human side of the story would probably skip the male uz part, and have Arroin, who has taken refuge in a magic dead zone, either to try to heal the Earth or to escape some enemy, meet a wounded KL. She has eaten something she should not, so Arroin courageously and selflessly accepts to be eaten to heal her from within. After he succeeds she lets him out again and they become friendly.
Depending on your take on Glorantha, and how you interpret Harmony and Life runes you could even have some R rated content. That could be a good way to cement a relationship.