26 month old with core body temp change from 97 to 100

Hi. My 26 month old son use to always have a rectal temp of 97 (+or -0.5 degrees), however for the past 30 days his rectal temp has been between 99.8 - 101, generally averaging at about 100.3. I know he doesn't have a true fever (our peds practice considers 100.5 fever), but this seems like a major change in core body temperature and my husband and I are now concerned.

He acts completely fine, plays, eat, drinks, sleeps all within his normal range (some minor changes here and there that are inconsistent enough to be due to be a two year old, I am guessing).

He started humatrope (human growth hormone) injections Oct 21st, but we have not noticed any problems with them. The pharmacist assures me HGH does not cause fever.

The rest of my baby's medical history includes:

Hypoglycemia at birth for six days (treated with TPN, formula supplements, IV fluids)

Coarc repair at 5 months (diagnosed and operated within 25 days)

Mild residual coarc

LVH of unknown etiology (they don't think it is from the coarc b/c the left ventricle should have healed by now, the LVH is not changing so they think it is either a normal variant or something we will discover with increased size/age)

Diagnosed borderline long QT's (not long enough to be considered Long QT syndrome, but long enough to avoid the risky meds for long QT syndrome; they suspect this is due to the coarc and not a true QT)

Multiple urological surgeries

And with all that relatively good health otherwise!

Should we be concerned? I know he is generally within the norms for temp, but my concern is the significant (or seemingly so) change in core temp. Is that normal? I am taking him in to sick call on Thursday (or normal doc is off on Wednesdays) to ask for a CBC at least. Assuming that comes back normal is there anything else I should ask them to consider? My baby has always been the "rare is rare" baby, so I am trying to not be paranoid, but also know he doesn't usually meet the "common is common" criteria.

Thanks for any suggestions or insights!!