You have to surf to cianwood, which is south of Olivine, and get the medicine in one of the houses there! Then go to the lighthouse and talk to Jasmine, and voila! Go get that biddys badge!
there will be a secret door at olivines lighthouse and it will take you to jasmine then go back to the gym then jasmine will battle you
Jasmine is the Olivine City Gym leader
In Pokémon Silver, you can find the medicine for the 6th Gym, which is located in the city of Olivine, by visiting the Olivine Lighthouse. There, you need to speak with Jasmine, the Gym Leader, who is worried about her sick Ampharos. To help her, you must travel to Cianwood City and obtain the Secret Potion from the pharmacy there, which you then bring back to Jasmine to continue your Gym challenge.
The fifth gym can be Jasmine or Chuck. No one is blocking any of the gyms. Although Jasmine might not be at the gym until you help the injured Pokemon.
After you beat Jasmine you go back to the city with gym leader Morty and to right of it which will lead you to Mohagany Town! Where you will face Pyrce (ice types)!! Hope I helped! :D
After talking to Jasmine in the Lighthouse, you have to go to Cianwood City and get a Potion from the Pharmacy there. Take it back to Jasmine and she'll go back to her Gym.
She's still in her gym.
the sexth gym leader jasmine is in the lighthouse
To get the Olivine City Gym leader to battle you, you have to go to the top of the lighthouse and help her heal a Pokemon by getting medicine from a man across the sea in Cianwood. The leader there, Chuck, is actually the fifth, and Jasmine is the sixth.
The 5th Gym is in Cianwood City in Pokemon Silver, Gold, and Crystal.
The gym leaders are: Falnker Bugsy Whiteney Morty Chuck Jasmine Pryce Clair Lt.Surge Sabrina Misty Brock Blaine Blue Jaine and Ekira.
You find her in oliveine city