Thanks for the query,
Probably you have developed thrombophlebitis
Your description matches with it.
It is an inflammation of veins.
Apply a mild steroid
Also take an analgesic
This will give you relief.
Please meet a dermatologist
for exact diagnosis.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.
Wishing you a good health.