Well, in current week I had two descent time sever pain in my frontal sinus. in two consequent flights.
So at least now I know what you feel !!
Yeah a sharp pain in frontal bone..behind my eyebrows..I was waiting for something to burst...barely stop screaming.
and you know what? I'm a GP doctor !
in 2nd flight I tried pseudoephedrine tab. and claritin...to no avail !!
but I guess the pseudo ephedrine was too early and a bit low dose...

recommended Dose..(yes you have every right not to listen to my advise!.. who couldn't stop his own pain!!!)

pseudoephedrine: 40-80 mg my recommendation is to take the pill 2 hours before start of descent ( that's the time of max effect)
don't take it if you have already hypertension .

benadryl: one pill is enough 2-3 hrs before descent.
not suitable for children under 1 yr.
also in syrup one big teaspoon. 2 hrs befroe d.

nasal wash sprays: one before flight and 2 or 3 times during flight.
if they let liquids into cabin !

nasal drop: phenyl ephrine: 2 drops each nostrill 15 min before descent.
if you have high blood pressure or glaucoma let's forget this drop.

If you are prone to likely pain during descent it is advisable (if you can accept my advise though!!) to take an advil tab 2 hrs before the descent to control probable pain. but don't take if you have allergy to this pill or stomach diseases.

Valsalva can be a help too. especially in ear problem.

if you have a sensitive frontal sinus you may feel the pain behind eyebrows and upper regions..
if the inflicted sinus is sphenoid and ehtmoid those eyepopping pain will show up..
maxillary sinus pain is settled in chick area..
nonetheless the treatment is the same....!