Adverse events arising from acupuncture treatment are quite rare. Safety surveys published in the BMJ a few years ago showed a likelihood of less than 1 in 10,000 of an adverse reaction to treatment. However, that does not mean they never happen.
In the first instance you should go back to the practitioner whom you are seeing to let them take a look at the problem. If the practitioner is a BAcC member he or she will be sufficiently trained in western medicine to recognise whether this is a temporary transient reaction or one which requires referral to a doctor. It will be useful to establish whether the part of the body where the inflamed spots are was in contact with any soaps, creams or lotions which might have penetrated the skin barrier. Since all the needles used by BAcC members are pre-sterilised, used once and then disposed of, the only way that a puncture point could become infected or inflamed would be from the needle carrying something from the skin surface into the dermis, or the puncture points not 'sealing' immediately after the treatment and something on the skin surface passing the outer payer of defence.
As a general point inflammation does not necessarily mean infection, and there are a small percentage of patients whose skin can react to needles in this way. This reaction is more often than not transient.