Hi,
my daughter (dancer) had Severs' when she was about 13.

Not sure whether the treatment protocol has changed, but when we got interventions, they were:
- stop dancing for 4 weeks; as pain improved, gradual return to dancing, then gradual return to competitions
- regular pain relief (combination ibuprofen and paracetamol) for 2 weeks, then as required
- Physio: deep tissue massage, stretches, and taping; the physio saw her twice weekly at the beginning, then weekly, fortnightly, etc.
- Home programme: daily deep tissue massage (I was shown how to do this) with a homeopathic anti-inflammatory cream (Arnica, etc.); this continued until pain had completely resolved, then gradually weaned
- Home programme: 3x daily stretches (3x 30 sec holds) - again, we were shown how to do this; the stretches changed over time; this continued until pain had completely resolved, then gradually weaned

This is just to give you an idea - treatment plans are individualised.
But if the treatment is not effective, return to your treatment provider.
They should be able to give you reasoning for their approach and information about the expected progress.

All the best,
Fyzzio