Dog has bumps on skin under fur. Should I be worried?

Hi! Realized as I was petting my dog that he as 5-6 bumps around his neck area that are yellowish. Will these go away on their own and are they harmful? He's never had any skin issues before.  

Hello!  This depends what's causing them.  Insect bites, for example, can swell and go down again, but some dogs react badly to them and one particular beastie - the flea - tends to remain local and continues to itch for some time.  This may also be folliculitis - infection or inflammation of the hair follicle.  Demodex mites sometimes perpetuate this, especially in dogs that have had some recent shock to their immune system.  You don't say how old your dog is re: allergies, and in any case allergies can start at a wide range of ages in dogs.  They can spread quickly and cause secondary infections.   So, what to do?  It seems reasonable to call your vets for triage.  If the lesion is shrinking rather than growing then you may have to wait for an appointment and there is always the chance that this is a fly bite which may 'go down' on its own.  However, some such lesions become itchy and the itchiness causes infections.  Wishing you all the best.

Rereading that, it may not be particularly helpful as to what to do next, so as a general rule: if skin disease or a hot spot is irritated and growing, then a vet check sooner or later is better.