Since you are allergic to paracetamol, you can take an NSAID like Ibuprofen (200-400 mg) or Naproxen for pain relief, provided you have no history of NSAID allergies, asthma, or stomach ulcers. However, experiencing a severe headache alongside eye pain while using Oflacin DX (which contains dexamethasone, a steroid) is a critical concern. Steroid eye drops can sometimes cause a dangerous rise in eye pressure. Please do not self-medicate further. You should seek immediate medical evaluation from an ophthalmologist or visit an emergency room to rule out increased intraocular pressure.