Since it's 2 days and the swelling is increasing in size, you should go and consult a doctor nearby.
You definitely need consultation as in Q&A we doctors can't see the swelling size, condition of overlying skin or if you have fever or not.
You can take allegra but it wont be too effective as according to you the swelling is increasing and it has been 2 days already
Next Steps
Get the swelling examined by a doctor
Health Tips
There could be infection (Cellulitis)!