Dr Bollmann, skin care specialist
Skin photodamage from the sun is the most frequent cause of wrinkles, as is observed in the image below. This woman has spent her life in the sun.
When the skin gets sunburned, it will tighten temporarily, but the skin is already damaged, and over time wrinkles will increase.
You can compare the effect of the sun by looking at your forearm - the undersurface is closest to your usual skin color and tone. The top side has sun damage.
No, the UV exposure from the sun will not contribute to skin tightness - just the opposite.
It is important to use sun block, applied every two hours while in the sun, and cover as many parts of the body as possible, including a hat.