Iran might choose to bolster its support to Hezbollah to help regain the lost ground. It might ramp up its financial, military, or strategic aid, or perhaps even become more directly involved.
Another potential path for Iran might be to diversify its alliances and investments in Lebanon and the broader region, to become less dependent on one group.
Alternatively, Iran might choose to step back and reassess its engagement in Lebanon, particularly if it deems the situation to be worsening or the risks too high.
Please note that all these possibilities depend on many variables, including the cause and extent of the setback to the close ally, the domestic and international reactions, and changes in the regional and geopolitical contexts. Without more details, it’s impossible to tell where Iran’s path could lead next.