You can give baby nurofen in conjunction with baby panadol if one does not bring the temperature down to your satisfaction. Other than that it sounds like you are doing everything right, keeping his cool and hydrated. If it creeps up any higher, or doesn't respond to medication, or if you see any other symptoms that cause you worry then a trip to your GP's will put your mind at rest, or to A&E if you can't get a quick GP appointment.