Worried about vein

The vein in my arm where the canula was put in is hard and knobbly. has anyone else had this? i had op on 25th june so just over 2 weeks ago and afterwards it was paintful and bruised. i had anti-sickness stuff put in the canula and that really hurt. i've googled it and it sounds like superficial thromboohlebitis, which is a clot in the vein so i'm a bit worried it might travel somewhere else! i'll phone docs tomoz but just wondering if anyone one else had it and what was the advice you were given?

Thankies x