Dear Srurhi, If your pricking sensation still persist even after a month of removal of FB then some portion of it may still be left. Secondly a thorough search of the FB should be made on slit lamp by everting the lids and staining the cornea to know if its rubbing onto it.Some of insect hair, exoskeleton, small glass piece are very difficult to locate unless someone make s thorough search. Since it is almost a month ,there are high chances of it forming a FB granuloma which also causes pricking sensation in eyes.So I would advise you to visit your nearest ophthalmologist once again and tell about your problem if it is haunting you on daily basis....TC...Dr Ajay Shankar Kar, cornea consultant, Sankar foundation eye hospital,Vizag.