The bite of bed bugs are always looking like this...
If your mark is looking like it..then you should follow some home remedies..
*Most important wash your clothes and bed sheets with hot water.
*Spray lavender, thyme, tea tree, or eucalyptus on bed linens..
*Spread some mint leaves on the effected area..as well as whole house..
*Use the combination of rapeseed oil and pyrethrins..It will directly attack on the bed bugs nervous system..
for more about this problem... read article... Bed Bugs Pictures