Hello ,
Your question does not specify the tooth and the area ,where it is horizontally placed.
Next Steps
1) xray is the basic requirement , for the proper treatment plan.
2) if the crown part of the tooth seems to be partially /little visible , then kindly keep that area thoroughly clean , so that there is no food lodgement ,as it may cause pain .
3) do warm saline rinsing 5-7 times in a day
Health Tips
1) it is always better to get the horizontally placed tooth removed as it will cause problems
2) mild pain killer and an antibiotic may reduce the pain . but it will be temporary and the pain will come back