I do not recognize the portrait. The only letters I can see are COS. Does the shape of the man's face ring any bells? The reverse is entirely obliterated with zero detail.
here are some possibilities Agrippa Struck under Caligula A.D. 37- 41 Æ As 28x29mm 10.6gm M AGRIPPA L F COS III; head left, wearing rostral crown. S-C; Neptune standing left, cloaked, r. holding small dolphin, l. vertical trident. RIC I Rome 58 Agrippa Struck under Domitian A.D. 81- 82 Æ As 26x28mm 8.6g M AGRIPPA L F COS III; head left, wearing rostral crown. IMP D AVG REST S-C; Neptune standing left, with dolphin and trident. RIC II Rome 825 Restoration Issue Under Domitian