What you need: Color-correcting concealer + cotton swab + translucent pressed powder.
What to do: To downplay a raised, red blemish, fewer layers of makeup are key. Dip a cotton swab in green concealer (green counteracts red) and dab onto the pimple. Blend into skin with your finger. Top with translucent pressed powder (which is typically more opaque than loose powder). Then avoid touching the area; the heat from your fingers can make the makeup melt.
RS picks: Make Up For Ever 5 Camouflage Cream Palette in No. 1, $38, sephora.com. Shiseido Translucent Pressed Powder, $32, shiseido.com.