  At half filling of the fourfold degenerate Landau levels |n| \geq 1 in
graphene, the ground states are spin polarized quantum Hall states that support
spin skyrmion excitations for |n| =1,2,3. Working in the Hartree-Fock
approximation, we compute the excitation energy of an unbound spin
skyrmion-antiskyrmion excitation as a function of the Zeeman coupling strength
for these Landau levels. We find for both the bare and screened Coulomb
interactions that the spin skyrmion-antiskyrmion excitation energy is lower
than the excitation energy of an unbound spin 1/2 electron-hole pair in a
finite range of Zeeman coupling in Landau levels |n| =1,2,3. This range
decreases rapidly for increasing Landau level index and is extremely small for
|n| =3. For valley skyrmions which should be present at 1/4 and 3/4 fillings of
the Landau levels |n| =1,2,3, we show that screening corrections are more
important in the latter case. It follows that an unbound valley
skyrmion-antiskyrmion excitation has lower energy at 3/4 filling than at 1/4.
We compare our results with recent experiments on spin and valley skyrmion
excitations in graphene.
