What can i do for the pain from phlebitis?

Heat: The pain of thrombophlebitis is from hsps, heat shock proteins. The most efficacious way of mitigating the effects of hsps is applied heat, such as a heating pad, plus nsaids like Motrin or alleve. Extremity elevation can also help. If pain fails to subside ove the next few days, a venous ultrasound is warranted to rule out dvt, deep venous thrombosis.

Anti-inflammatories: Reduce the pain of phlebitis with anti-inflammatories like ibuprofen, combined with an extra streength Acetaminophen blocks both pain pathways. Warm compresses, compression stockings help. See a vein specialist to evaluate the cause, like a superficial vein clot, which can be treated further.

Compression: Besides the things that dr. Presant mentioned inn his excellent answer, leg elevation often helps. Wearing compression stockings helps too.

Pain-phlebitis: If the phlebitis is superficial, use of Arnica gel locally over the area may be of benefit. However I would recommend the use of a compression stocking during daily activities to help with venous return. If the phlebitis is deep, and inflammatory reaction is set up, and anticoagulation therapy will provide some reduction of the inflammatory reaction.