<s>[INST] Hello, My son has recently been receiving allergy shots twice a week in both arms for about a month now.  I just noticed that in his right arm is an indentation that is darker than his arm, also the tricep area is swollen. He has been taking Benadryl, but no change.  Is this normal? It's been this way for almost five days now. Thanks [/INST] HIThank for asking to HCMThe dark area that you are seeing could be the healed area beneath skin, that becomes dark once the lesion gets alright,( Reactive lesion ) this will remained dark still few days then this will be fine, no need to take any medicine for this, have nice day. </s>