B747-400 First Officer reported they descended below glide path due to wind shear and received a glideslope warning.

Narrative

On ILS approach to RWYXXR at ZZZ with Captain as PF in VMC. At around 900ft I asked for a wind check and approach end wind on the RWY was calm and we had a current headwind of 35kts. We prepared for the wind shear by increasing a Vref by a few knots. Crossing the coastline we were coming through the wind shear and got 3 reds on the PAPI so I called 'slightly low' and the Captain responded 'correcting'; we then momentarily drifted lower to the point where we got a 'glide slope' call and 4 reds on the PAPI at the same time. It happened so fast; the Captain increased thrust and we landed on the runway. I should have called 'go around' as soon as I saw the 4 reds or the glide slope call out.Wind shear on short final. In the future I will monitor the approach more thoroughly and at the first sign of instability I will be more assertive and call for the go-around or wind shear escape (if wind shear).