Very concerned about lumpiness on one armpit after mini brachiolasty. Does it need revision, or just swollen?

It is very early in the healing and settling process. It is normal for some left to right differences in swelling, lumps,etc which are usually temporary.Continue Close follow up with your plastic surgeon and following post op instructions are recommended. 

Hi, Thank you for the question. 5 days post-op is really very early to make any kind of definitive judgement on if you need a revision. It is very normal to have swelling, brushing and mild asymmetry in the early post-op phase which is usually temporary and self-limiting. The role of following diligently the post-operative instructions can not be over emphasised. Make sure you see your PS on a regular basis and don't wait at home if you suddenly feel unwell, the wounds are discharging or become smelly.