The pain and slit on gums can be due to impacted wisdom tooth
which is erupting.
I would suggest you to get a clinical EXAMINATION done.
If wisdom tooth is impacted,it has to be either extracted or flap overlying tooth has to be removed to enhance tooth eruption
Maintain oral care.
Gargle frequently using warm saline or betadine
Take complete course of antibiotics-analgesics prescribed.
Hope this helps.