You know your folck best, but that doesn't look severe to me. Yeah maybe some dehydration. And many reasons for pale comb good to notice that.
Some facts would help, age of bird, is she laying still, any recent additions to flock. How long have you had them. Have you changed nesting material, feed, anything?
how do you provide water, open container, nipple, cups?
In mean time, checking waterers to see if they are clean... really clean, taking apart the components and really getting the gunk out- chickens are gross... just a fact, and watering areas and devices get dirty.
A few are more picky about how and what they drink.
Add a little molasses or rooster booster to clean watering to see if she's more interested.
Good luck