Wire getting into gums, might be of two reasons,
1. Gum infection ( gingivitis);due to deposits, please go for a professional cleaning and treatment for the same.
2. Might be the retainer got damaged, please check for it and if so get it corrected.
Next Steps
Please visit the dentist and rule out the exact reason for the problem
Health Tips
Can consult the orthodontist, whether it is the permanent retainer or it can be discontinued
If it is the permanent one, go for another or retainers of recent technology.
You should give extra care for oral hygiene when retainers are placed, as it might destroy the previous ortho treatment done.
Hope this helps you