Air carrier Flight Attendant reported a fume event during cruise resulting in the cabin crew experiencing physiological symptoms. Upon arrival cabin crew were removed from return flight.

Narrative

I was the #2 galley Flight Attendant working Aircraft X. I detected an odor of something resembling a diesel smell. I contacted the Captain to advise him that there was definitely an odor in the aft galley. I communicated to the Captain that I had checked the lavs and walked to the wings and detected only a faint smell. Flight Attendant #4 Name had a hard time speaking; became hoarse immediately and her eyes were puffy. I suggested to her to go up front to the forward galley for the remainder of the flight. I donned an O2 mask in the aft galley and remained on it until the aft galley door was opened by catering. #3 also donned an O2 mask for landing occupying the aft jump seat for #4. All 4 F/A's (Flight Attendants) had headaches and sore throats by the end of the flight. Upon arrival in ZZZZ we had medical personnel check our [vitals]. We called Scheduling and requested to be taken off the flight and had ZZZZ airport manager arrange a hotel and limo for crew rest. I immediately upon arriving at the hotel took a hot shower. Once out of the shower I noticed that I had a nosebleed. I sat down pinch my nose and after a few minutes the bleeding did stop. I took two Motrin for my headache and started to hydrate. I had a faint headache the entire night. I woke up the next morning and met my crew for breakfast and complained of a headache and sore throat. We spoke about how upon landing the mechanic had come on board to say that there was a fuel leak in the number two engine and that they were going to have to open the engine and take a look. We also spoke about it breakfast they need to do a report. Our pick up was at XA:00 so I went back to the room to lay down. Upon entering my room I had another nosebleed and I decided to call [contract medical advice]. [Contract medical] arranged transportation to the hospital and I was seen by a doctor in about 30 minutes. My blood pressure registered 190/80 which my normal blood pressure would be 100/60. After two hours of observation with my blood pressure not going down the doctor decided to admit me. I stayed until the next day with some medication to bring my blood pressure down and headed home on Sunday. I was seen by my doctor on Monday for bloodwork and follow up medical advice.This was definitely a fume event that caused injury to my crew. I would like Company to take a fume events more seriously in the future and any absence occurred would not be a poor reflection on my attendance work record. I still have not been credited for the trips that I missed due to my hospital stay.