But if she has a sinus infection, that congestion lasts longer than 10 days and does not respond to an over-the-counter decongestant.
The National Institute of Allergy and Infectious Diseases noted that in 2009, about 31 million adults reported having a sinus infection, also called sinusitis, which has several symptoms in addition to the nasal congestion. The duration can be up to four weeks (acute sinus infection) to more than 12 weeks (chronic sinus infection).
People suffering from a sinus infection can do some home remedies to help reduce the congestion from the sinus infection. For example, MedlinePlus noted that inhaling steam, such as from a shower, two to four times during the day can help with congestion. Using a humidifier and spraying with nasal saline may also help. Other home remedies that may alleviate the nasal congestion from a sinus infection include placing a warm and moist washcloth on the face multiple times.
https://www.empowher.com/sinus-infection/content/treatment-sinus-infection