A bump on your tongue that's painless and has lasted over a month, even after the surface rash cleared with the antifungal gel, is worth getting examined rather than treated blindly from a distance. It's likely ongoing irritation or a thickened area from the earlier rash, but anything persisting this long under the tongue's surface needs a direct look, especially since the gel hasn't been able to reach it properly.
Next Steps
Please see a physician or dentist who can examine the inner tongue directly and decide whether it's still the fungal process or something else. Mention that it hasn't resolved after a month of antifungal gel.
Health Tips
Get it checked sooner if the bump starts growing, becomes painful, bleeds, or swallowing becomes difficult.