Injured was using a wash down hose to clean on and around the 3 East No.4 belt drive. After EE's work was completed EE was going to cut the wash down hose off. The injured slipped/fell while cutting the handle off on the hose. EE then inadvertently pressurized the hose. The hose came loose from EE's hands and struck EE in the left side of EE's forehead near hairline. Caused cut.