In this passage, Aime Cesaire describes his worries of how colonization of his homeland has affected the people, language, and culture of the original inhabitants. Upon his future return, he anticipates seeing the "hideousness of your sores", which is in sharp contrast to the condition Cesaire is returning in ("sleek and young"). I believe that this is most likely a description of mental health, as Cesaire has been able to maintain a clear mental state by preserving the original culture and language of the island. The line, "Embrace me without fear..." shows how Cesaire is worried about the resistance of some of the original inhabitants to return to the study and use of their original language. After the initial resistance to colonization and change subsided, the inhabitants, who were quickly adjusting to the new imperial cutlture and language, would likely be unwilling to undergo another cultural change.
The last part of the passage is less clear. However, I believe that the part saying, "beware of assuming the sterile attitude of a spectator" is Cesaire saying that while the culture and language of the people appears to be dead, it does not mean that the people have no desire to revive their roots. It could simply be a result of a lack of any organizing figure or institution to lead them back to their language.