about engine noise

hello sir, my honda city ran very low on oil due to some accident. i got the oil pan repaired and put the oil. now the car is running fine. it is having normal acceleration pickup etc. but it is having some noise when engine touches 2500-3500rpm. sound goes off at higher and lower rpms. the arcs on connecting rods are damaged as i can see to it. i want to ask if the main bearings on crank can be damaged? further if i dont get them replaced will there be any further damage? please reply asap. thank you