Do not worry ,all cancers are not inheritable.Some are sporadic also .Your father diagnosed with Gastric carcinoma may increase risk in subsequent generation but does not land you in cancer definitely.
Next Steps
Try to maintain oral hygiene and gut health .
Health Tips
If symptoms persist / worsen for more than required duration kindly go to ENT doctor for further evaluation of tongue and gum related problem .and for teeth related problem you can consult dentist .