Type III veins, intradermal veins are 1-3 mm in size. Foam sclerotherapy is ideal for those. Read the description below.
What you are describing appears to be blue/red reticular veins. These veins are larger than spider veins but smaller than varicose veins. They tend to be more prominent and visual in thin/lighter skinned individuals. The best treatment for these veins is sclerotherapy. See a vein specialist.