FCOM 3.2.70 P11 (Eng 1/2 Fail) suggests the following as indicators of damage:
Loud noise
Increase in vibs or buffet
Repeated or uncontrollable (engine) stalls
Abnormal indications eg loss of hyd fluid (or oil quantity)
No N2
NB A windmilling engine will give about 3% N2 but no oil pressure at V2+10 so no oil pressure is not necessarily an indication of damage.
mcdhu