Since you are already taking a strong antibiotic and an antiallergic, please allow 48 to 72 hours for them to show full effect. For immediate relief from deep congestion, you can temporarily use an over-the-counter nasal decongestant spray containing Oxymetazoline or Xylometazoline. Use it only twice daily and limit use to a maximum of 3 to 5 consecutive days to avoid worsening your congestion (rebound effect). Alternatively, an oral decongestant like Phenylephrine may help, but avoid this if you have high blood pressure. Please consult your prescribing doctor before adding any new medicine.