Cant get over 300 First Aid on Blackrock

As the title says im stuck at 300 First Aid on Blackrock. I have no problem when i create a character except DK. Normally when i create a Character it does not have First Aid at the beginning so i go to the NPC at Daralan Mall and learn first Aid so i get it at 450 maxed out. But when creating an DK , it does have First Aid already at 300 , going to the NPC to learn First Aid doesnt do anything so i stuck with First Aid at 300/300. Since there are no NPCs outside i have no clue how to fix it and get past 300 First Aid. Please help.