After my second Infini that I had 2 weeks ago, I have strange reaction on my neck that looks like raised bumps? (photo)

This is not an uncommon reaction. Inflammatory responses can cause these bumps.  A steroid ointment applied twice a day will settle these bumps down. Please be patient, this is not a permanent sequelae of the procedure.

I have been using Infini in my practice for almost 4 years, and I have seen this transient side effect of tiny bumps (at the needle insertion sites) twice.  In both cases, the bumps were on the neck and completely resolved within one month (prior to the subsequent treatment session) without intervention.  Infini is a very effective device;  I use the device most often to treat crepey (finely wrinkled) skin on the front of the neck and for acne scarring.

Sometimes little things like this happen. Whether the skin is reacting this way temporarily or this is a side effect that will require intervention can only be determined by someone taking a look in person. However, if these are a semi-permanent reaction, they can be treated with chemical peels, fractioned ablation (Profractional) or a similar laser. For now get some silicone gel (over the counter) and use that twice a day. 

This is part of the process of Infini. It will subside after a few more weeks. For severe cases, I will sometimes use a VBeam or Excel V laser to calm them down, particularly if they are red. Doing nothing is ok as well. It is the coagulated debris being broken down by the body prior to the collagen formation. 

This not an unusual reaction, your specialist will know how to settle this down with a short course of anti-inflammatory steroid ointments for a few days to a week. It does take up to 8 -10 weeks to settle down completely and is not permanent. Dr Davin Lim.