It could be a couple of things.
The BA/BB Ratio ~ Benzyl Alcohol and Benzyl Benzoate.
If EO is being used ~ Ethly Oleate used as a Solvent to Thin Out higher Concentration Gear.
Or it could be you are Allergic to the Carrier Oil.
Your Best Bet is to contact the Supplier, and ask them.
What is the BA and BB percent in the Test E.
What Carrier Oil is being used.
And is Ethyl Oleate in the Compound.
Get that Info, and I can answer your Question in more detail.
Lots of people have Problems with Test E @ 300 Mg/Ml.
So you are not alone in that regard............................... JP