Medium Transport First Officer reported encountering wake turbulence on descent into BOS that caused violent rocking; rolls in both directions and autopilot failure. Control was regained; the flight landed safely; but reporter stated because of workload the yaw damper was not turned off before landing.

Narrative

Flight ABCD ZZZ to Bos descending on the JFUND2 around 15000ft. Aircraft rocked violently 15 degrees right bank then left 15 degrees. I believe we encountered wake turbulence from an a321 10 miles ahead. Autopilot fail message was presented and autopilot disconnected. I took control of the aircraft and continued the arrival the captain ran a QRH and checked with FA to make sure the cabin was OK. During the arrival we got a runway; change and shortcut; causing the workload to be very high for both of us we were able to continue and land from a visual for runway 4 left however I forgot to disconnect the yaw damper before landing. After landing; the captain noticed the yaw damper was on and disconnected it.Cause: High workload during arrival and approach caused task saturation for both Pilot flying and Pilot monitoring. More proficiency with hand flown; arrivals; and approaches would help keep skills up.Suggestion: In the future; I will press the auto pilot disconnect button at minimums so that the Yaw Damper is disconnected when hand flying approaches. I will also hand fly more arrivals and approaches so that in non-normal situations I am more proficient.