Stop using the lens immediately, and do not mount it on your camera until it has been inspected. Salt water can cause rapid corrosion and, if moisture reaches electrical contacts, may also damage the camera body.

The safest recommendation is to take it to a camera service center as soon as possible. Internal droplets mean water has gotten inside, and salt residue is especially harmful over time.

If professional service is not practical and the lens is otherwise a loss, some people try a very thorough rinse in fresh water followed by a long, slow drying period. This may reduce salt contamination better than leaving the salt in place, but it is risky: coatings, lubrication, and internal parts may still be damaged, and residue can remain on optical surfaces.

Do not expect distilled water or drying alone to fully solve internal salt contamination. Even if it still seems to work now, corrosion and optical issues may develop later. In many cases, replacement may be more realistic than repair, especially for a lower-cost kit telephoto lens.