Wombat, quite right. Self-medication can worsen the condition.
GP-wise it is vital that you find one that understands aviation medicine as well. I was once prescribed nasal drops to be applied by tipping my head back and using a pipette to put drops down each nostril.
My barotrauma would have occured in an unpressurised aircraft in a high speed descent from high level. Aside from the risk of hypoxia had I removed my oxygen mask there would have been a loose article risk with my holding bottle in one hand and pipette in the other. Finally, with a helmet it would have been impossible to tilt my head back.
I was cleared to fly but the Doc was so ignorant of aviation medicine, and this on a flying unit, that I refused to fly.
For a passenger, if you get a sudden onset of ear ache man up and call the flight attendants. They may offer a decongestant and request the captain, as a medical emergency, to ease the rate of descent.
The bottom line remains DO NOT FLY.