Expensive light. Whether it’s worth it to deal with a return is up to you. Shipping from the US to China is not cheap.
Personally I’d probably pull the lens, dry it out when apart (let the reflector dry, don’t rub), inspect ALL the parts for burrs and assembly issues, make sure the O-rings are OK, and put it back together.
If you got water under the lens just from a ‘rinse’ I suspect something was not done right there.
One of the issues is a hot light going into cold water. The outside is going to cool rapidly and create some negative pressure/suction. If it’s not well sealed water can be VERY invasive.
Conversely, just putting it in a desiccant is not likely to be very useful. If you put it in a WARM/150-170* oven with the desiccant you ‘may’ have some success….maybe.