Major Swelling - Maybe Horsefly Bite?

Got stung or bitten yesterday morning and since then my arm has gradually swollen up to the size shown in the picture. Went to the pharmacy today and was given Loratadine to try and reduce the swelling in the form of a one a day tablet.

Any suggestions? Should I go to the doctor? Its slightly leaking a puss like substance and its quite itchy, tender and hard in the middle, and pretty firm on the rest of it. Swelling seems to still be slowly increasing.

Thanks

[Dr. Kokil Mathur]

Hi
Thanks for writing to the forum!
Please consult a doctor. There is a chance that the sting of the insect is still inside. In such a case the allergic reaction will not fade completely unless it is removes. Also you will need to take anti-allergics and anti-inflammatories to complete the treatment.
Please let me know if there is any thing else and do keep me posted. Take care!